How to deal with approving quality Tenant Screening

[Kham Sing]

What happens if you already know the person trying to rent your unit does not qualify? Should you allow them to look at the place and filled out the application? Or can you tell them straight out that they don't qualify already and not let apply? 

Current reason not qualify: 1. Temp Job  (income not stable) 2. Person just got out of prison after doing 2 years for DUI 5th.  3. Fact that they are living in a motel for the mean time. 

Thanks in advance!