Makkot 3 - False Witnesses About a Divorce
Two witnesses said, "We testify about this man that he divorced his wife (that is, gave her a Get), but has not paid her the Ketubah." Later they were found to be false plotting witnesses.
In this case, they cannot be made to pay the full value of the Ketubah, which they wanted the husband to loose, because he may have to pay her the Ketubah anyway, if he divorces her or dies. Instead, the court estimates the trade value of the Ketubah, that is, how much would someone be willing to pay for that woman's Ketubah, on the understanding that he may not get the payment at all, and the false witnesses pay this amount to the husband.
A similar case is where two witnesses said, "This man borrowed money and needs to repay it within thirty days," whereas in reality the loan term was ten years. If they are found to be false witnesses, they pay the amount that a person is willing to pay for having the loan in his possession for the extra time, and this is not prohibited interest.
Art: French Unknown Masters - Portrait of a Couple