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.Today's Date: Medi-Cal Access Program. A gift letter for a mortgage is a written statement confirming that the gift money you receive from a family member or friend is a gift, not a loan. 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. We'll also show you how to write a gift letter with a gift letter template so you can help your donor prepare for underwriting. A gift letter is a note from a donor to your lender regarding cash funds for your mortgage down payment.