Tell him. Go to him and acknowledge your debt and the promise not kept. Let him know that you love him and thank him again for helping you. Tell him you don't want to loose his trust or his love. If you can pay any portion of the money now, give it to him. Make some kind of commitment, that you are sure you can keep, to get him the rest of his money. Finally, if you can't borrow from a bank you should never borrow from a friend or relative. Instead go to the person or company to whom you are indebted and tell them your situation and work out some kind of an arrangement.