[If a woman said,] “I was given a yavam overseas,” [and then] she added, “my husband died and then my yavam,” [or,] “my yavam [died] and then my husband” —- she is believed. [If] she and her husband and her yavan went overseas, [and] she said, “My husband died and then my yavam,” [or,] “My yavam [died] and then my husband” —- she is not believed; because a woman is not believed to say that her yavam died, so that she may marry, or that her sister died, so that she may enter his household; nor is a man believed to say that his brother died, so that he perform yibum with his wife, or that his wife died, so that he may marry her sister.

A woman whose husband and co-wife went overseas, and they came and said to her, “Your husband died,” may not marry or be taken in yibum until she knows if her co-wife is pregnant. [If] she had a mother-in-law, she need not concern herself. [However, if] she departed while pregnant, she must concern herself. R' Yehoshua says: She need not consider it.