It all depends on her upbringing and how much she cares about her religion/pleasing her parents. That's it and that could be said for any background.
My cousin got married to a Catholic girl. They had been dating on and off since junior high school; I think everyone pretty much knew it was going to happen. They have been married a few years and not once have any religious issues ever come up. My brother has been dating a Christian girl for a few years now. They're pretty serious and have been living together for a while. And me? I married a Japanese girl last year, and religion is the furthest thing from my mind. If anyone in my family has a problem with this, then they've kept it bottled up for a long time. My mother did go into a semi-panic mode when she found out I proposed, going off with the whole "HOW WILL YOU HANDLE HOLIDAYS?!?!?! HOW WILL YOU RAISE YOUR KIDS?!?!?!?!?" spiel, but the thing is...I could give two shits about religion. My wife doesn't care either so this is a non-issue, but my mother just couldn't seem to understand this. She never has and probably never will. However I was going to marry my wife no matter she thought, and I laid that out right away. Haven't heard a word about it since. She is the only one in my immediate family that even keeps kosher, BTW. And that (and everything else) is pretty much to keep my Grandfather happy, I think.