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. The purpose of this letter is to document that the money does not need to be repaid as well as the donor's name, contract information, and relationship to you.Sample of a Gift Letter. Used when getting a new mortgage and getting a gift from family. Mortgage Gift letter is what the donor of the gift writes to the lender stating that he has offered a gift of money to the home buyer. You can use gifted funds to make a down payment, but your mortgage lender will want to know some details before they allow you to use it. A gift letter for a mortgage is proof to the lender that money you've been given for your home purchase is a gift, not a loan to be repaid.