Headcanon: Normally, when Steph gets hit on or checked out, she brushes it off pretty easily. She doesn't think she's a supermodel or anything, but she's confident with her looks, and the flowery words are just that. With Dmitri, however, he somehow reaches to that part of her that can still find that sort of thing flattering, and she has a love/hate relationship with that. He can make her blush all too easily, and she secretly loves it.
//See, this goes a few ways and gets into where Steph's head is about your boy, you tricky critter!
As Dmitri goes, he reminds her of the guys she used to know when she was growing up. He says a lot of things that pull a smile from her, but she gets this feeling that he says that to plenty others too. She enjoys the game and the chase of it, Steph's always liked that part of a relationship. The thing that makes Dmitri stand apart from those guys to her is the fact that he still respects her. He couldn't not respect her and have wanted to fight her and try his luck against a Bat. That takes him up a notch easily.
The thing that gets her is he doesn't let up, he's just completely shameless and she's not even that bad normally. And you know this girl can flirt. So. Yeah. The shamelessness tends to be what gets her heated in that love/hate kinda fashion. Hopefully this makes sense.