I always find these discussions kind of funny because, let's be real, the canon material doesn't exactly hand it to us on a silver platter. The whole dynamic starts with Boa's obsessive infatuation, which is played mostly for laughs, and Luffy is... well, Luffy. So in fics, you've gotta bridge a canyon of emotional disconnect. The good writers don't just magically make Luffy reciprocate—they slow-cook it. They lean into his core trait: his ability to see past surfaces and understand people's pain. So maybe he notices her flinches around the word 'love' or her over-the-top protectiveness stems from a deep fear of losing someone again. The connection grows from him being the only person who isn't dazzled by her beauty, but who sees the lonely, traumatized woman underneath. It's him being his usual self, offering unwavering loyalty and protection to a nakama, and her gradually realizing that what she feels is shifting from a one-sided crush to a real bond built on mutual trust. Honestly, the fics that fail for me are the ones where he's suddenly all suave and romantic. The ones that work make the romance a byproduct of their established dynamic—her learning to be vulnerable with someone who won't exploit it, and him gaining a fierce, devoted ally who understands the weight of his dreams in a way maybe even the crew doesn't.
A lot of them use physical touch, but not in a cliché way. It's Luffy grabbing her hand to pull her along on some adventure, completely oblivious, and her realizing his touch doesn't feel like ownership. Or her trying to mother-hen him after a battle and him just accepting the care in his own simple way. The emotional payoff usually isn't a grand confession; it's a quiet moment where she stops declaring her love theatrically and instead just says she'll follow him, and he gives her that trademark grin and says 'Shishishi, okay!' That feels real to the characters. The growth is entirely on Hancock's side, learning what healthy attachment looks like, while Luffy's affection manifests as including her in his circle of absolute trust.