Is this a good tenant?

A sales man , household income is $650,000, 2 kids, 3 cars. gave me  a fake landlord reference but i find his real landlord by using onlin people  search  who said he has been lived in the aptment for a year and pay rent on time. The sales man only give me his first page of  year 2010's tax return. Refuse to have his credit checked. He said he will drop the house if I check his credit. his reason is  that his credit score will be lowered each time somebody check his credit. Do you think he is reliable to rent?