Renting a room in a house I'm about to buy

[Craig Champagne]

Because it's a room in my house and the new tenant will not be a relative...my question is this...if you create a lease will it stand up legally? A contractor told me if the renter burns down the house with his hot plate, the homeowners ins won't cover it because he shouldn't be there in the first place....I want to be covered all the way around..,what do others do?