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 goal of a gift letter is to provide the lender with proof of where the funds came from.Mortgage Lenders Require Gift Letters. A gift letter for a mortgage shows your lender that you don't need to repay gift money toward your down payment. A mortgage gift letter is a legal document whose primary purpose is to state that down payment funds given to the borrower are not expected to be repaid. 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. A gift letter is a note from a donor to your lender regarding cash funds for your mortgage down payment. The letter needs to indicate that the money is a gift and not actually a loan you must pay back. And, the letter certifies that the money does not need to be repaid which is a must for down payment gifts. It states how much you're getting and from whom.