1,591. When a Woman Must Take an Oath
Hilchos Ishus 16:18
Whenever a woman cannot collect the value of her kesubah without taking an oath, the court advises her to take the oath and collect her money. Whenever a woman can collect without an oath, the court tells her husband to pay her because his claim cannot be accepted without proof.
Hilchos Ishus 16:19
If a husband asks that his wife take an oath denying his claim, the court advises her to take the oath and be paid. This oath is taken while holding something holy. If the couple had previously agreed that the wife could collect the value of her kesubah without an oath, or that her word would be accepted in any situation, then she can collect without ever taking an oath. This is only the case in the event of a divorce; should the husband predecease the wife, she must still take an oath in order to collect from his heirs.