A/N: Hello, this is my first and probably only ever attempt at a OUAT fanfic. I was rewatching some of the episodes where Emma and Killian first meet and interact and had so many feels! This idea just popped into my head and is the work of a couple of hours solid writing so please be gentle!

Disclaimer: I do not own Once Upon a Time. If I had there would have been more Captain Swan in season 3...

"Reasons why I, Killian Jones, love Emma Swan."

Fact: Killian Jones loves Emma Swan.

He was pretty sure he loved everything about her and eventually set out to prove it to himself. He was never quite sure however when proving his theory went from a practical and logical plan to determine his feelings to a full blown habit or addiction of stating his love. He could remember how it all started however and it involved several bottles of rum, some thievery and many, many feelings that he couldn't quite define.

***Killian***

He had been in Storybrooke for a while. Accompanied Cora to the World Without Magic (which now had magic so that was a bit of a stupid name for it but he didn't quite know how else to call it as it had no defining features like the Enchanted Forest or Neverland so the name stuck) and had been planning how best to destroy his nemesis.

The only problem was he kept getting distracted. His distraction came in the form of a certain blonde Sheriff who kept catching his eye and his attention and she had been doing so since they first met.

One night he got rather exceptionally drunk and he made a list. A list of all the things he loved about Emma Swan in an attempt to clarify his thoughts about the blonde and with a clearer head he would be able to concentrate on his plan(s) to kill the Crocodile.
Stumbling around his cabin on the Jolly Roger with a pad of paper and a pen that he'd nicked from Granny's Diner placed neatly on his desk and a bottle of rum in his hand he rambled to himself.
Every now and again he would cross to the desk, put the precious rum down and instead pick up the pen and scribble down one or two items on the list next to numbers (because he was methodical and practical and wanted to take stock of all his thoughts the following morning and know exactly how much his feelings amounted to) before retrieving the rum and swigging down more.

The list was very long.

It started off with the first thing he noticed about Emma Swan:

1. She's bloody brilliant. (When she called him out on his deception at their very first meeting. Her putting all the clues together from his surviving Cora's massacre right through to his lie. Wasn't often he met a woman who couldn't tell when his words weren't true.)

After that he went through a few more facts that were rather standard.

2. Her eyes.

3. Her hair.

4. The way she quirks the corner of her mouth when she's amused but trying not to show it.

5. Her body (because he could spend years looking at it and find it as beautiful as the first time he saw her.)

He even found himself listing random things that he hadn't even realised that he had noticed about her. The little things that she did, like:

28. She bites her lip when she's excited. (as if she has to hold back childish squeals of delight).

37. Her favourite film when she was a child was Oliver and Company.

39. She loves hot chocolate with cinnamon but she also sometimes likes hot chocolate with a shot of brandy.

43. She wishes her hair was curly.

55. Her favourite time of day is dawn (she sometimes wakes up early and pulls on her coat and boots and drives up to the hill above Storybrooke with a flask of tea and a tub of cookies to watch the sunrise. He saw her doing this several times whilst he was staking out the Crocodile's shop).

79. She cannot bake. Her cooking isn't bad but ask her to make anything remotely resembling a form of cake and the kitchen will be destroyed.

83. She has dreams of Henry telling her he doesn't need her almost every night. (Emma wasn't the happiest tipsy person and she tended to spill out her darkest secrets to the bottle. Killian of course had been a gentleman and shadowed her home to make sure she didn't get into trouble. She never quite worked out how she ended up back at the apartment when her last memory was of sitting down on a bench near the park. Killian never told her that he carried her home and knocked on the door until Mary Margaret came down to open it.)

91. She doesn't like the rain.

93. She always wanted a dog as a pet (he overheard her saying that to Ruby when she took Pongo to her flat after Archie had "died").

Somewhere after the 111th reason Killian finally collapsed on his bed and passed out from all the delicious and frighteningly clarifying rum he had consumed. The following day they headed into the jungles of Neverland.

***Killian***

He hadn't missed the place where no one ever aged. It was as horrible and terrifying as he remembered and this time he had no crew to back him up or to overwhelm the Lost Boys with. Instead he had the two Charmings, The Evil Queen and Rumplestiltskin who quickly vanished from their company. And Emma. Beautiful, stubborn, courageous Emma who desperately wanted her boy back.

Killian kept the pad from Granny's and the pen hidden in one of his pockets. One of the secret pockets of course that was hidden inside his coat (a pirate always has hidden pockets and secrets). Sometimes when he was on watch, in an effort to stay awake and to occupy his weary and worried mind he would read the list and add things.

113. She plays hard to get. (He never quite knew where he stood with her and she always surprised him.)

117. She still trusts people even though she has been hurt so many times (he wondered why she even trusted him sometimes. He had double-crossed her a couple of times but then again she'd done the same to him.)

Then they ended up back in Storybrooke and he lost her before he'd even had her.

***Killian***

He was both relieved and angered when they reached the Enchanted Forest to discover that he had his pad with 132 reasons why he liked Emma Swan on it. He wished the damned thing had been lost in Neverland. Or that he had left it behind in the World Without Magic. Or that he had never started writing the cursed list in the first place.

All the time he spent trying to find a way back to her and to Henry (whom he had started a tentative friendship with) he couldn't look at the pad. Couldn't see all the reasons written out before him and not feel her absence like a hole in his heart.

When he finally made it back to her Killian felt his heart soar when she opened that door even though she didn't recognise him and the kiss didn't work. He knew it was true love on his end and that he could wait for her forever if necessary.

Back in Storybrooke however being part of the "Hero" group was a strange experience and one he wasn't entirely comfortable with. Too many morals sometimes and Charming could be thoroughly aggravating sitting on his high horse and always looking down on the pirate.

He couldn't complain however as it meant he got to spend more time with Emma and he found himself adding new things to his list at the end of the day when he returned to his room at Granny's B&B.

151. She has the phobia Scriptophobia (which Killian found out when she was asked to sign a birthday card whilst they were having dinner at Granny's one night. The look of terror on her face had caused him to accidently spill his whiskey and her attention had been diverted to his disaster. The person with the card had beaten a hasty retreat at the dark glare the pirate sent towards them and later Emma had briefly mentioned her fear but never told him why she had it).

157. When she was little she wanted to be a ballerina (one of her the rare good families she ended up with took their entire family to see a production of Swan Lake. She loved it but then only two days later they sent her back to the orphanage).

163. That she secretly thinks Regina is the best badass. (Emma had been slightly tipsy when she admitted this fact and had drunkenly slurred about how even though she was 'kinda evil Regina always dressed to stun, had awesome powers and was pretty damn cool').

Killian felt his hopes crushed when Zelena cursed his lips. To have Emma coming so close to him, finally trusting him and letting him in more, only to have to thrust her away from him was torture. But he couldn't let Zelena win, couldn't let Emma lose her powers, and couldn't bring about the Unhappy Endings of everyone Emma cared about.

His pad went back into a hiding place in his room in Granny's B&B. All his focus went into protecting Henry and Emma.

After defeating Zelena he wrote one new thing on it before secreting it away again.

189. She sacrificed her magic to save his life.

***Killian&Emma***

Killian watched as Emma pushed and pulled him away again and again but he never wavered in his love and affections for her. Even when she was dealing with Regina and Elsa he stood by her ready to catch her if she fell or support her if she needed it. His pad filled up with more and more reasons as time went by but he didn't write in it as frequently as he once had. He had the real Emma to be with and didn't need to list his reasons except for sheer pleasure of noting the tiny things.

When everything calmed down again and Storybrooke finally experienced its first calm period since Emma entered the town, Killian found himself moving in with her and Henry. It was then his list writing began once again but this time it was filled with the delicious notes of one who saw an Emma Swan that no one else in the world had ever seen or saw.

232. She dances around the apartment when she thinks no one's home.

248. She has five tattoos, three from before Storybrooke and two that she added after.
The first one she had gotten when she turned the legal age, a black and a white swan with their necks entwined to represent her name and her love of ballet hidden on her left thigh.
The second a quote from Peter Pan (which Killian found strangely ironic given the World Without Magic's portrayal of his life and Neverland and how Emma had found her life entwined with his) "All the world is made of faith and trust and pixie dust." curled over Emma's right shoulder.
The third was Killian's least favourite and it was one which Emma rarely left uncovered. A tiny dreamcatcher that hid behind her right ear and could only be seen when she put her hair up. She had told him about her time with Neal and whilst Killian mourned the boy he had once known and the man he had come to know he could not approve of the person Bael/Neal had been when Emma had been in his life.
The fourth tattoo was one Emma had done after the First Curse was broken, sometime after she and Mary Margaret returned from the Enchanted Forest. It was on her left forearm and rose up from her wrist to the crease of her elbow. Henry's storybook was open on her wrist and then up her arm magical tendrils had been drawn until they reached a perfect miniature rendition of Snow and Charming's castle. Within the tattoo were symbols that depicted each of Emma's family; a sword for Charming, a bird for Snow, a cupcake for Henry and there was even an apple for Regina because in some weird way she was family.
Emma's final tattoo was another Peter Pan reference in a way but this time it was purely for Killian and it was his favourite. His hook decorated her right wrist with the word "Trust" curving around it and within the circle made by the metal was Killian's name. He loved that tattoo most of all.

259. She looks adorable in her glasses. (Killian loved that no one apart from he and Henry ever saw her in her glasses. She only needed them to read small print but he loved the way they framed her face and how much younger they made her look.)

261. She's too shy to walk around naked. Even in the middle of summer and when Henry was staying over at Regina's she would always put a pair of pyjama shorts and a strappy top on if she needed to leave the bedroom.

264. She has a weakness for British period dramas. (Killian couldn't see the attraction in watching Pride and Prejudice or Jane Eyre or North and South but Emma loved them. On nights when she was feeling particularly tired or upset all Killian had to do was put one of her period dramas on the TV, bring her a glass of wine, a blanket and a bowl of popcorn and let her curl up under his arm on the sofa and she would brighten up almost instantly.)

276. That she would get extremely jealous if another woman laid a flirtatious hand on him. (One of the only clubs in Storybrooke had attracted a rather rowdy and raunchy clientele one night and as he was assisting the Sheriff and Deputy Sheriff, Killian had accompanied them to help move on the crowd of intoxicated and horny young people. Killian's black clothing and tight leather jacket had caused one of the younger and more lascivious girls to get rather close and personal and Emma's jealousy that night had been thoroughly expressed when she had smashed a mirror. Of course the smashed mirror and thoroughly irritated looking Sheriff had sobered up most of the club's guests and they beat a hasty retreat. Killian had, had to pay for the mirror however.)

289. She always calms down during a nightmare if Killian rubs his stump on her back.

290. She loves his stump and has never shied away from it.

***Killian&Emma***

Years later Killian still had his list and it had well over 400 reasons why he loved Emma on it and every now and again Killian would pull it out from the box he kept it and the original pen in, and scribble in a new reason. Apart from those odd occasions he all but forgot about it so busy was he living and loving Emma.

For some reason however it never crossed his mind to show it to Emma and he always hid it away until one inevitable day she found it.

They were doing something Emma called 'Spring Cleaning' but Killian privately thought it was just an excuse to rummage through their belongings and reminisce (but he wasn't complaining about spending time with Emma) when the box fell down from the shelf in their wardrobe and the contents spilled out on the floor.

There were various items in the box: photos of their life together and with Henry and the Charmings. A shell that Emma had given Killian on their first date when they had walked along the beach. A wristband that Henry had made at school for the pirate. And of course the pad with the reasons.

Emma knelt on the floor with the box and looked over each item carefully as she replaced them to make sure they weren't damaged or broken. She had seen many of them before and finally she had returned all but the pad and pen to the box. The notepad had fallen face down so it wasn't until she picked it up that Emma realised what was written on it.

She recognised the handwriting instantly as the well-educated calligraphic style that Killian always wrote in.

"Reasons why I, Killian Jones, love Emma Swan" was the bold title and Emma felt her mouth open in a silent exclamation of surprise. As she read down the list she felt her heart swell and her emotions caused it to beat rapidly. Each reason was carefully noted with occasional accompanying explanations and Emma devoured each and every one.

In the years they had been together Killian had never given Emma reason to doubt that he loved her but they had never really said why they love each other. The whole True Love thing sort of indicated that they were meant for each other and that they were a perfect match but Emma had never really thought about why Killian had fallen in love with her.

"Emma?" Killian's voice called from the hallway. "Have you seen my phone? I'm supposed to be arranging a sailing trip with Henry and your father but I can't find the damn phone under all the Spring Cleaning you're doing."

She could hear his footsteps coming along the hallway to their bedroom but she couldn't move. Couldn't hide the notepad, couldn't stop reading the reasons, and couldn't stop the happy tears falling down from her cheeks.

"Emma?" Killian said worriedly as he entered their room and saw her knelt on the floor. In mere strides he was across the room and crouching down next to her peering at her with concern. His eyes fell on the notepad and Emma glanced up in time to catch the blush that spread like wildfire across his cheeks.

"Ah." He coughed and scratched at the back of his head with his hook. "You uh, you found my uhm, notepad?"

Emma nodded and wiped away the tears with the sleeve of her shirt.

"Mmhmm."

"I can explain! I was really drunk one night on the Jolly Roger and I didn't quite know what I was feeling so I started to write things down trying to make sense of it all and it turned into a list of reasons why I found you attractive and then it just continued on from there lass, I didn't mean to keep adding things to the list but it became quite cathartic and I liked finding out new things about you and new reasons why I love you so I just kept doing it, like a good habit you know?"

Killian flustered and spluttered and Emma stared at him with wondrous eyes.

"Say something lass or I think I might have a heart attack." Killian said nervously.

Emma waited a few seconds before launching herself at her pirate and planting a kiss solidly on his lips. His arms swept up to cradle her to him and she pressed herself against him and wound her hand deep into his hair.

She pulled back from the kiss enough to mumble,

"God I love you Killian. You damn, romantic, old pirate!" before plastering his face with kisses.

***Emma&Killian***

Later that night Emma began her own project in her own notepad:

"Reasons why I, Emma Swan, love Killian Jones."

1. Because he made a list of why he loves me.

2. Because he's Killian Jones.

3. Because he understood me.

4. Because he never gave up on me.

5. Because…

A/N: Thank you if you read all the way to the end! Please let me know what you think as I've never written for this fandom before and nothing so fluffy...