I don't think you are running a rental business. Am I right?
You can tell him, with polite and no-offensive words, that you don't feel comfortable with his lifestyle.
If you still don't feel comfortable to tell him the truth, you can just tell him a lie that you have already had a roomate, and say sorry to him. That's it.
You can tell him, with polite and no-offensive words, that you don't feel comfortable with his lifestyle.
If you still don't feel comfortable to tell him the truth, you can just tell him a lie that you have already had a roomate, and say sorry to him. That's it.