Personally, after my last experience with a roommate who claimed to be vegetarian, but then told me two days after moving in, "But I really love pork chops," I wouldn't let anyone live with me who wasn't at least ovo-lacto, and I would make sure that the person understood that Veg does not mean chicken or fish. I would get it in writing.
The "I won't eat meat in the house," promise sure didn't work for me. I found beef enchilada and McDonalds burger in the trash, shrimp in the fridge, and pieces of ham in the sink drain. When I reminded her of her promise, she said, "It isn't like I'm murdering a cow in your kitchen." I learned to hate her. I would prefer not to have that kind of soul sucking in my life again.