A pre-approval letter, is harder to obtain, but gets the tumbs up from sellers. The home buyer will go through the actual approval process including, but not limited to, credit checks, debt to income ratio surveys and verification of down payment. The pre-approval letter does state that the bank has made a preliminary approval of the loan and is willing to complete the loan process in order to finalize the sale. The pre-approval letter does not, however, lend a definitive answer as to whether the sale will go through. Before a final sale, the buyer will again have to go through a credit check and present the down payment.