A/N: I woke up this morning to a discussion on Twitter about 5.19's "I love you". Some were convinced his lack of reaction meant she had said it already, regularly. Others were disappointed. I've always been surprised that this was a thing in the fandom, because to me Kate saying "I just want you" would mean more to Castle than a thousand "I Love Yous". Anyhow, here's my quick and dirty response to all of the above, dedicated to the wonderful Twitter crowd- the best virtual friends a girl could ask for.

Disclaimer: After 5x19, who can doubt true ownership of these characters?

I never loved nobody fully

Always one foot on the ground

And by protecting my heart truly

I got lost in the sounds

-Regina Spektor, Fidelity

The first time she said it, she was drenched on his doorstep, whispering apologies and pleading with him. Ok, the next morning, during those heart-stopping few moments he awoke and discovered she wasn't there, he had replayed the entire evening in his mind and realised what she actually said was "I just want you." Four words instead of three. But after she had an understanding with Bracken and Gates had instructed her to wait out her suspension before coming back and they finally had time to breathe again- although who can be bothered with fine details of things like breathing when Kate Beckett is spending her suspension showing him every different meaning of the words "I just want you" was beyond him- he had realised that technically she hadn't said the words yet.

Only he didn't want the words.

Well, he did. But he had four words, and to him, they meant more than three.

"I just want you" meant she had chosen him over her war. Over her mother's case. Over the very thing that had defined her. The thing she had reminded him just the day before in their bitter fight in her apartment was the most important thing in her life. Rick Castle was nothing if not a master of subtext, and was familiar with the old adage 'show, don't tell'. That night, dripping and desperate on his doorstep, she'd shown him, all right- with every slide of her tongue against his, every whispered confession of exactly what had transpire in his absence, in the openness in her eyes as she gasped against him.

He didn't need "I love you". He'd heard those words before, and still was left bleeding. He had whispered them to her before, while she was bleeding, and then they had festered between them months later when he discovered she had lied. "I just want you" meant so much more.

This doesn't mean he didn't love also hearing the words.

The first time he heard them, he hadn't even been sure she'd said them. It was a late night phone call in the middle of the Du Pree case, after a rather memorable handshake had left her aching with need in the middle of the precinct. She had called him far too many hours later as she entered her apartment, exhausted but wanting him, and they had whispered sweet and dirty nothings to each other as she slid into her all too empty bed. They would have fallen asleep just listening to each other breathe, except her phone kept digging into her ear or sliding across the pillow, so she had ended the call with an adorably mumbled "Night, Castle. Love you." He had blinked awake to stare at his screen as the call cut off, trying through his sleep-addled brain to figure out if she had actually said it or if he had dreamt it.

When the horror of Tyson's return was dealt with and she was finally able to take him home, she had spent several hours reclaiming him with the blinds drawn, explicitly whispering words of love and reassurance over and over, culminating in a breathy "I love you" as she shattered over him, around him.

Since then, the words were used with more and more frequency in the bedroom, but it wasn't until after a particularly spectacular Valentine's Day and then the drama of Alexis' kidnapping and subsequent return that the words began to creep out of the bedroom and across the loft and her apartment to the breakfast bar and sofa.

He knew her, though. Knew that she knew him. In fact, since Meredith's visit, it had felt on occasion like she was claiming him with her knowledge of his mind, his heart. She knew that her love was desired, sought after- but it was her good opinion that he craved. He had her love since she showed up dripping at the loft, but her respect was something he would spend a lifetime attempting to be worthy of.

So when the words were casually thrown around his home now, he didn't blink. He had her heart, just as she had possessed his for so long now he almost didn't know when it started. They intermingled, intertwined- and yet were both individuals, completely complementary to one another. He knew that she knew as she casually threw the words across the loft how his mind got caught up with things, even though she might be frustrated in the moment. She knew him, and he her.

And then she surprised him.

Best. Girlfriend. Ever.