Yevamos 14:9-15:1

Yevamos 14:9

Let’s say that two brothers, one of whom has congenital deafness and the other of whom has all his senses, are married to two unrelated women, one of whom has all her senses and the other of whom has congenital deafness. If the man with congenital deafness married to the woman with congenital deafness dies, what does the brother with all his senses married to the woman with all her senses do? He marries her and if he wants to, he may divorce her (but not perform chalitzah). If the man with all his senses married to the woman with all her senses dies, what does the brother with congenital deafness married to the woman with congenital deafness do? He marries the widow and can never divorce her (because the Biblical yibum connection trumps his rabbinic ability to divorce).

Yevamos 15:1

If a woman accompanied her husband overseas in an overall peaceful situation, then she returns and reports that he died, she may remarry or perform yibum as appropriate. If the couple had peace between them but there was war in the world or vice versa, then if she returns and reports that her husband died, she is not believed. (If there is war in the world, he might just be presumed dead; if there is marital strife between them, she has an ulterior motive to lie.) Rabbi Yehuda says that a woman is never believed to report that her husband died unless she appears in court crying and with torn garments (as a sign of mourning). The Sages replied that it makes no difference whether or not she shows signs of mourning, she is always believed and may remarry.