Waaaah, I can’t please everyone. The Bible says you shouldn’t, but it also says to love everyone. BUT, I personally wouldn’t mind if my fiance weren’t a Christian, as long as he respected my religion. And when people ask me things on here, I assume they want the biblical advice more than my opinion. So IDK. Bottom line; I really don’t think it’s a sin to marry, like God won’t be mad at her for doing that, as long as she doesn’t let him/their marriage to effect her faith in Him. But I am not God. So I’m not exactly sure.
One last thing;
Maaaany marriages fail due to conflict in religion, so it probably wouldn’t be a good idea.
It all depends on the couple. If they want Christ at the center of their marriage, they both basically have to be Christian. The morals may be drastically different in the two people though.