They were just hanging out in the guild, as usual, when she came to her realisation. Lucy had finished up an interview with Sorcerer Weekly, now a bit tired from also having done two minor jobs. She had accidentally said yes to Jason when he called late at night a few days ago, at the moment not remembering that the date was occupied by not only one, but two jobs. Wendy and Erza wanted to go on a quest that could satisfy their sweet tooth - not an easy task when Erza set her mind to it, and Natsu had made her agree to killing a smaller monster that had been pestering an old woman's garden. Though these missions may sound like easy jobs, they have a tendency to become more complicated whenever Fairy Tail is involved.
Yes, Lucy was tired, but she was still happy. Erza and Wendy baked a wonderful cake that they shared with her, the old lady was glad to have her garden safe and sound, and Jason had pitched a great idea for his article thanks to Lucy's tips and support. Making the people around her would never get any less satisfying, no matter how much she did it.
At the moment Lucy was sitting alone at a table close to the bar. She had left her book at home, and most people were already heading home for an early weekend. Across the guild hall Warren and Max sat deep in conversation, and a few metres away Natsu and Happy were singing some old nursery rhyme. Seeing how some of the older men were shaking their heads, they probably weren't getting the lyrics right, but when they sang so confidently no one had the heart to stop them.
As the singing died down, Lucy got a good look at her two best friends. They often resembled father and son in Lucy's eyes, even if they tried to act like strictly best pals. Because despite their unconditional friendship, their bond couldn't be described with those words. They didn't cut deep enough. Yes, Natsu was a good friend to Happy, but whenever they calmed down she saw affection deeply grained in his eyes. The way his smile softened around Happy, and the way his sharp eyes got a soothing gaze - they were nothing else but fatherly love.
Lucy knew Natsu could get insecure with how he had raised Happy. At his young age, raising a baby became a game of trial and error, which he understood when he got older to be less than optimal around such fragile creatures. Plus, being abandoned (even by accident) by his own father at a young age, meant that he never felt quite sure in his parenting methods. Luckily Fairy Tail stood by his side during these years, and despite the ups and downs that came with living this life, Happy became a wonderful exceed. Lucy hoped Natsu knew what a wonderful life Happy had led thanks to him, because he had put so much effort and determination into giving Happy a safe and, well, happy life.
Lucy found Natsu completely remarkable. The man had been through hell and back multiple times in his life, and always came out smiling. Truthfully, Lucy might just believe him to be invincible. He had lost very few serious battles during all the years she had known him. Sure, a match against Makarov, Gildarts or Erza was practically never a win, but she had this feeling deep within her heart that made her believe that if he ever met an opponent their strength or stronger, Natsu still wouldn't lose. He's the strongest mage Lucy can think of - his physical strength might not be the strongest in the world on its own, but combined with his beastly magical capacity and his never ending flame of love and determination, he could be deemed unstoppable.
What impressed Lucy the most was the way he had grown to be this way all thanks to his own mindset. One could be abandoned by their father and end up in a dark guild or begging on the streets, but Natsu wandered around until he got found and taken in. One could be ridiculed for their naive and childish ways and fall into a depression, or get filled with copious amounts of rage, but Natsu didn't. He has always used that to his advantage, making enemies confused, or he has used these traits to joke around and make friends with the most unexpected people (Gray might be an exception to this - if Gray ridicules him, Natsu meets him with a fist). And the list goes on! People can go bad from losing their parents right in front of them, they can go bad from watching loved ones die right in front of them, etc etc, but Natsu always bounced back brighter and stronger. It was the most attractive thing about him in Lucy's opinion. Well, almost.
Lucy couldn't properly describe Natsu without mentioning his love for his friends and his guild. She had long suspected that the one true magic was love, but it was made so clear when she met Natsu. When she tagged along to Mt. Hakobe in order to find Macao, she saw it with her own two eyes - Natsu was always fighting for all of his friends. No matter what the fight was or who he was up against, he carried all of his friends on his shoulders, and with time and effort they grew, along with the love he had for them. The fact that Lucy was even counted for when they were fighting the Macao-vulcan, made her question his sanity sometimes. The boy who had expressed nothing but annoyance at her when she tagged along, still swore in his name to protect those he cared for - no matter how much they bugged him. Because at the end of the day, Natsu had still picked Lucy up in Hargeon, and that was to him enough reason to fight for her.
Natsu's love was like nothing else in the entire world. Lucy knew she shared the sentiment with the rest of the guild, who all in some way had seen his complete love and trust for the guild in action. She knew this, but sometimes she thought that being his closest companion, she had probably seen it a bit more vividly than the others. Lucy felt Natsu's love every second with him. She felt it when she fell asleep on her writing desk and woke up in her bed the next morning. She felt it when they were outside and Natsu put his arm out in front of her whenever he heard something slightly suspicious. She felt it when she found post it-notes on the fridge with apologies for eating something she had bought, or with promises to go grocery shopping for her the next time she had to go out. His love was radiant in every waking action - actually, let's rephrase that; in every action, awake or not, because she never forgot the times he would sleep in her bed and unconsciously make room for her when she got in, and she never forgot the times he'd give her more of the blanket when her temperature seemed to go down.
Natsu loved loudly and greatly, and for that Lucy loved him even more. She truly loved it all, his pink soft hair that he styled in the morning with the heat from his hands, his unruly, expressive eyebrows that always showed all his emotions like an open book, his deep, dark, loving eyes that could look so fierce and so tender, his adorably crooked nose that twitched when he smelled something nice, his sharp but welcoming smile that could hold the anger of a dragon and the softness of a father all at once. She loved his body that protected, carried and fought for his guild, and she loved his silly choices of clothes that had to be specially tailored. She loved his lighthearted personality that drew out the child in everyone he met, and she loved his amazing sharp fighting senses that not only made the jobs they went on easier, but also made them more fun than she ever knew work could be.
Dear God, how she loved him. And the best part? She would get to love him forever, because that's the one promise she knows he'll do anything in his power to keep. That's what she loved the most.