1,592. Absolving a Woman of an Oath
Hilchos Ishus 16:20
If the couple had previously agreed that the wife could collect the value of her kesubah from the husband’s heirs without an oath, or that her word would be accepted in any situation, then she can collect from the heirs without ever taking an oath. However, if she goes to collect from property of her husband’s that has been sold, she must take an oath in order to be paid. This is because even though her husband was willing rely on her word, the condition that he made only applies to himself and his heirs. He cannot agree to terms that obligate others to incur a loss.
Hilchos Ishus 16:21
A widow who has her kesubah can collect what is owed her after taking an oath even if 100 years have passed since her husband died. This is true regardless of whether she continues to live in her husband's house or has returned to her father's house. If she doesn’t have her kesubah, she cannot collect from the heirs even if she makes her claim on the day of her husband’s death. Similarly, a divorcee cannot collect even the baseline amount of her kesubah without producing the actual document.