פירוש על יבמות 15:1

Everyone is trusted to testify for her on this matter, except for five women who presumed to hate each other, such that they may not testify as to the death of her husband, lest they intend to prohibit her upon him and he is still alive. And these are: her mother-in-law, even if she is not currently her mother-in-law just her levir's mother (Tur), the daughter of her mother-in-law, her rival wife, her husband's brother's wife and her husband's daughter. And so too she may not testify for them (Tur).

One witness says "he died", and [another] witness says "he was killed". Even if they contradict one another, since each one agrees that he [the decedent] is no longer alive, she [the deceased's wife] shall [re-] marry.

If a single witness came and testified that her husband died, and they permitted her to remarry on his word, and then another witness came and contradicted the first witness, saying, "He did not die," she is not removed from her permission, and she may still remarry, for a single witness with respect to a woman's [remarriage] testimony is believed just like two witnesses in other testimonies; the subsequent testimony of the single [contradicting] witness is negligible in the face of two witnesses. Note: Nevertheless, because of the risk of slander she should not remarry (Tur). However, if the second witness came before the court permitted her to remarry, she is not permitted to remarry, and if she did remarry, she must divorce, because it is doubtful. If she married the witness who testified that her [previous] husband had died, and she says, "It is clear to me that he died," she need not divorce. But some authorities say that [even in this latter case] she must divorce. If two witnesses came forward and said, "He did not die," even if she already remarried, all authorities agree that she must divorce. Note: This applies when she is silent, but if she says, "He died," it is considered as two witnesses (i.e. the wife and her supporting witness, c.f. Bet Shmuel) against two witnesses as long as all the witnesses are women. But the husband who married is not considered as reliable for himself [against the two subsequent witnesses] (Nimukei Yosef, chapter haIsha Kamma). What are the circumstances of this ruling? When the single witness upon whose word she remarried can be considered as two witnesses against the two witnesses who later came and contradicted, as in the case where she remarried on the word of an adult male who was contradicted by two adult males saying, "He did not die;" or she remarried on the word of an adult female or her own assertion, and two subsequent female witnesses or two Rabbinically invalid male witnesses came and said, "He did not die." But if a kosher (valid adult male) witness said, "He died," and numerous women said, "He did not die," or invalid male witnesses said, "He did not die," this is viewed as half against half. Note: This applies when the witnesses arrived together before the court permitted her to remarry on the testimony of the first witness. But if the court had permitted her to remarry on the testimony of the kosher witness, and then the invalid witnesses arrived, she is not removed from her permission to remarry (Tur). If she married one of her witnesses, and she says, "It is clear to me that he died," she does not need to divorce. Note: Kuthites who are conversing innocently have the same status as invalid witnesses (Mordechai chapter haIsha Bathra), but a Kuthite who is not conversing innocently (e.g. he knowingly claims to the court that the husband died) is not reliable whether to forbid or permit remarriage.