A gift letter from the donor verifies that the money is a gift that does not need to be repaid versus a loan which would need to be repaid. A short letter like this sample gift letter will cover all of the requirements your lender needs.Down Payment Assistance Loan for. A gift letter for a mortgage is a document that confirms that a financial gift has been given to a borrower to help them with the down payment or closing costs. A gift letter for a mortgage shows your lender that you don't need to repay gift money toward your down payment. If so, check which ones: â–¡ Phone â–¡ Trash.