Sa’if 10, Mechaber: A person, without being sued, voluntarily tells another any one of the following things: He borrowed money from him, he held an item on deposit for him, or he stole from him. However, the person volunteering this admission also says he is uncertain whether he repaid the money or returned the deposit. In all of these situations, the person volunteering the admission is exempt from any payment.
Nevertheless, if he wants to go beyond the black-letter law and exonerate himself ethically in the eyes of God, he should pay the amount in question. If, however, he tells the other he does not know for sure whether he borrowed money from him, whether he held an item on deposit for him, or whether he stole from him, since he volunteered this statement in the first place, without being sued, he is under no legal or ethical obligation to pay anything.
Ner Eyal: In the first case mentioned, the person who volunteered the statement admits that he did, in fact, owe money to him at one time. Therefore, in order to exonerate himself ethically in the eyes of God, he must pay the money even though he is uncertain whether or not he has already repaid it. In the second case mentioned above, the person who volunteered the statement is uncertain whether he ever borrowed money from him, held an item on deposit for him, or stole from him. Therefore he does not even have an ethical duty to pay anything.