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. 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 for a mortgage shows your lender that you don't need to repay gift money toward your down payment. A gift letter is an important, formal, legal piece of documentation that can help explain that a (usually rather large) sum of money was gifted to you. The goal of a gift letter is to provide the lender with proof of where the funds came from. Mortgage gift letters tell the lender that money for your loan came from a gift. Lenders require gift letters when necessary. A gift letter is a written explanation provided to your mortgage lender when someone else gives you money toward a home purchase. To use gift funds, you must provide a gift letter proving the money is not a loan.