Any ideas on how to pick a border?

I am seriously considering renting out one of the rooms in my basement. It is a decent sized room and there is a bathroom down there as well. The border would have to shower in one of the bathrooms upstairs and come and go through the front door. With kids in the house it is imperative that I get someone trustworthy. Has anyone done this type of thing before? Any tips on how to find and keep the right border?