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 is a legal, written statement your lender may require if you're gifted cash to buy a home.What is a gift letter? A gift letter is a document that certifies the funds you're receiving for your down payment are a gift, not a loan. A mortgage gift letter is a statement that assures your lender the money that came into your account is a gift and not a loan. How to write a gift letter. Below is a template for a gift letter, useful when family or friends want to help you with a loan downpayment. Yes, this is normal. We bought our first house just before we got married. A mortgage gift letter must include the donor's name and information, the gift amount, and other details about the home and gift.