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 gift letter for a mortgage shows your lender that you don't need to repay gift money toward your down payment.A short letter like this sample gift letter will cover all of the requirements your lender needs. A mortgage gift letter is a document that helps satisfy the requirement that a borrower's down payment funds come from legitimate sources. 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. A gift letter is a note from a donor to your lender regarding cash funds for your mortgage down payment. If you use gifted funds toward your home purchase, your mortgage lender will need a gift letter to explain that the money is not a loan. A mortgage gift letter states that you received money as a genuine gift to use toward a down payment, rather than a loan.