The letter must explain who is gifting the money, where the donor's funds are coming from and the relationship between the donor and the recipient. A short letter like this sample gift letter will cover all of the requirements your lender needs.Here's a sample gift letter you can use to prove that the money is truly meant as an outright gift, with no expectation of repayment. This guide explains how to document gift funds for a mortgage and meet lender requirements. How do I open an account? A gift letter for a mortgage shows your lender that you don't need to repay gift money toward your down payment.