Whether you have known your prospective roommate since kindergarten, or whether you just met, it is important to set aside some time for an in-depth conversation to discuss your expectations. You should meet in person, perhaps over a cup of coffee.
Campus is a great neutral ground.
A telephone call just won't do for something as important as this. Thoroughly explore how each of you feels about the other's comments. Better now than after you sign a lease. If either of you paints too rosy a picture, you are in for some nasty surprises later on. If you live with someone long enough, your true feelings will eventually come out.