I was unsure about the romance stories myself, especially because I played a female smuggler at first and couldn't stand Corso even as a lightsider. And then the flirts in the jedi knight story line that start off the romance just after the end of act 1 come off as really awkward. But Kira is an interesting character and I decided I'd be missing out on a nice chunk of story if I didn't try.
In story wise, my explanation is really the circumstances. My character kinda always had this friendly teasing back and forth banter with her. So there never really was a teacher/student aspect and she never seemed like a subordinate, so my Knight never felt like he had any right to lecture her on her opinions. Plus even if he disagreed he'd be too polite to say so. So he ended up listening to her a lot and eventually conceeding that she had some valid points.
At some point harmless banter became flirting without him really noticing that he was doing that. All the problems she had going on and her real story got him caring about her more then just as a friend, and she started dropping hints the size of a battle cruiser that eventually became so obvious even he picked up on them. And then she liked him enough that she overlooked how terrible he is at the turning up the heat come-on thing. He was raised a Jedi Knight, of course he'd be terrible at it.
Then act one ended and they were both a little messed up trying to deal with what happened, combine with being there and comfort and maybe some admittedly questionable judgment, and there you have it.
Basically, I need to know how this conversation plays out later on. If I take the option that I'm too fond of her (54 point affection gain), the conversation ends with no kiss, and she seems disappointed.
Well, I gave her a gold necklace as a gift just before this conversation, rp-wise as a recognition of her becoming a Knight, and she didn't get any affection gain. After this conversation, she started to like those kinds of gifts. So I think that conversation really is the make it or break it moment for the relationship, and you might have to go all in here or miss out.