Responsa for Bava Batra 308:10
אמר רבי זירא אם יכפור רבי יוחנן ברבי אלעזר תלמידו יכפור ברבי ינאי רבו דאמר רבי ינאי אמר רבי מודה בשטר שכתבו (אינו) צריך לקיימו ואמר ליה רבי יוחנן רבי לא משנתנו היא זו וחכמים אומרים המוציא מחבירו עליו הראיה אין ראיה אלא בקיום השטר
[have the same power as if] all depended on him!<span class="x" onmousemove="('comment',' Once he himself admitted that he wrote the deed, it is assumed that no witnesses would have signed it if it represented a purely fictitious transaction, and, consequently, even the Sages agree that he has no further power subsequently to invalidate it. Hence, no attestation is needed. ');"><sup>34</sup></span> But, Resh Lakish asked him again, in your [own] name it was reported that, 'the members of the family have justly protested'!<span class="x" onmousemove="('comment',' Although they admitted the authenticity of the deed, (i.e.. that the seller had written it), and only disputed its validity (by asserting that he was a minor). How, then, could R. Johanan say that once a person admitted the authenticity of a deed, (i.e., that he wrote it) he cannot any more dispute its validity? ');"><sup>35</sup></span> — He replied to him, 'This [was] said [by] Eleazar;<span class="x" onmousemove="('comment',' A disciple of R. Johanan. ');"><sup>36</sup></span> I have never said such a thing.'
Teshuvot Maharam
A. A trustee appointed by both parties is not required to take an oath regarding the terms of his trusteeship. But, Leah was not appointed trustee by both parties. She was only appointed by the husband, and, therefore, is required to take an oath. Leah's husband cannot object to imposing an oath on her. If the law requires that a woman take an oath, the husband has no right to protest against her being degraded in court. But, since Leah, as long as she is married, has no money of her own, and were she to claim that she had already returned the deposit, no oath would be imposed on her, we now lend credence to her words and require no oath. However, the court should give A a writ stating that after Leah will be divorced or widowed she will have to return the money to A or take an oath to the effect that A deposited the money with her on condition that she return it upon his wife's consent only.
SOURCES: L. 306–7; Mord. B. K. 89. Cf. Pr. 739; Tesh. Maim. to Mishpatim, 44.