Faith's Links
Truth be told, he hardly knows her. He doesn't quite trust her... but then he doesn't quite trust anybody. He thinks she's a little too snooty and upper class to be hanging around Eden, but if Eden is happy then so be it.
At first, Eden thought she was stuck up and he wanted nothing to do with her. Fate intervened, though, and kept forcing them into situations together that forced the both of them to learn about one another and to grow. Somewhere along the way, Eden fell in love with her. He still has plenty of times where he thinks he's not good enough for her and she'd be better off finding someone else, but he loves her and he's doing his best to take care of her and love her.
Logan is not going to be kind about it: he thinks Faith is a bitch. Maybe he would have been more lenient or more mildly amused by her upright act, but the minute that she started insinuating (like his father did in the past) that Logan would just go right back to the drugs and the alcohol and that he didn't deserve Kartini it was over. He may be okay with Kartini having a relationship with her sister but *he* sure as shit isn't going to.