L.W.
my family has had rental props since I can remember..they rent based on credit, referals and personal experience. If the credit is good, great,...if they have good referals (pay on time, good renter etc) then good regardless of their credit score..OR if someone has bad credit, and they needed a co-signer for the lease(in my parents situation, this girls father co-signed)
If you are really worried...make them have a BIG deposit...if they want to live their...they will make it work regardless of their credit...I say work with them, but give them some hard rules....(big deposit..you miss one month, you are out..type thing)
EDIT...I wanted to add after reading a couple posts...just because someone is a good person, that doesnt mean they will try to stretch the generosity you have given them or push the envelope...some of my best friends who are good people, have ripped others off left and right....just saying
peace ladies