How does one win Faith's heart?
Um. Poker?
It's not all that hard, actually. Canon Faith falls for people incredibly easily, although I don't think she can tell the difference between platonic, romantic and sexual but I might be missing something in the translation there. She'll follow you around, back you up even when you're kind of wrong. Act like your prison wife no matter how new your friendship is. She'll become your body guard, your long lost pal as well as other Paul Simon-like stupidity.
But she's very, very fragile and she hates being passed over, rejected or made to feel apart from everyone else. She can and will break every bone in your body if your hurt her feelings (depending on her age/the year - older Faith is a little more stable, a little less eager to give you a chance though) so it's best to just let sleeping dogs lie because the kind of damage someone like Faith can do to you if she's heartbroken really isn't worth the 'winning' of her heart to begin with. You don't want Faith to love you, trust me.