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. Sample of a Gift Letter.Used when getting a new mortgage and getting a gift from family. The goal of a gift letter is to provide the lender with proof of where the funds came from. 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. A gift letter for a mortgage shows your lender that you don't need to repay gift money toward your down payment. 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.