Well, it depends on the personality of the girl and on the girl individually. Even if she really is into her religion I think it depends on if she respects you enough for you to have your own beliefs. HOWEVER, I'm not going to sugarcoat things and tell you that a person with different religion, ethnicity, or socoioeconomic status is as easy as pie to have a relationship with. There will be things to work through. Extra things, in fact. But it certainly is not impossible.