So we learn from the Pasuk (verse) that a father who says he gave over his daughter to a certain man is Ne'eman. He's relied upon to give testimony, and we believe him about whom his daughter married. Normally, we would need two edim. We need two witnesses to give testimony about somebody. But uniquely in this scenario, we believe the father on an individual basis because of this Pasuk. So if the father says, “I married off my daughter when she was a ketanah (minor),” or, “I married her off and then she got divorced when she was a ketanah,” and she's still a ketanah, the father is believed to tell us anything about his daughter's marital status. But this is only while she is a ketanah, while she is a minor. That was the context of the Pesukim. But if he says that right now she's an adult, she's older, when the father is making the statement, when he's proclaiming it, the father is not believed. The father is only believed to give testimony about his daughter while she's a ketanah. It's not only about the action; she still has to be a ketanah for the father to be believed. In this scenario, she's an adult. Therefore, the father is not believed to give any sort of testimony about his daughter's marital status.
Halacha (Jewish law) is that a woman who was taken captive is not allowed to marry a Kohen (priest). When she was taken captive by somebody, taken hostage, we have the assumption that they raped her. A woman who was raped by ovdei avodah zarah (idol worshippers), by goyim (non-Jews), has the din (status) of a zonah (woman forbidden to a Kohen). A zonah is not allowed to marry a Kohen. So unfortunately, this woman was taken captive. We'll talk about whether a father is believed to say that his daughter was taken captive. The Mishnah says, “Nishbet u'feditiha: My daughter was taken captive by the ovdei avodah zarah, by the goyim, and I ransomed her. Bein she-ketanah, bein she-gedolah, eino ne'eman: Whether she's a minor or an adult, she's not believed.” Therefore, she wouldn't be allowed to marry a Kohen. A father is only believed because of the Pasuk. That pasuk deals specifically with marriage, and we connect it to divorce, not to any other matters. The father is not believed.
Now we'll talk about yibum. Yibum is when a man passes away with no children and he has at least one brother; that brother is obligated to marry his widow. We'll talk about a situation where it was assumed that the man had no brothers and no children. His wife would have been exempt from yibum because he had no brothers for her to be with. But then he claims that he has children. She'll still be exempt from yibum because we make the assumption that he has no brothers. Or there could be another situation where he says that he has no children but he has brothers. That would obligate them in yibum. Because if he has brothers and no children, his wife would be obligated in yibum. The Mishnah says that somebody we thought had no children and no brothers says, right before he dies, that he has children from another marriage. Ne'eman, we believe him. Since he has children from another marriage, it doesn't change the status of his wife. We made the assumption that he had no brothers either. Therefore, when he tells us he has children, it doesn't change the situation, and we believe him because there was no yibum as it is. But if he says, “I have brothers,” we assumed he had no children, and we assumed that he had no brothers either. But now he's telling us he has brothers. Because he has brothers, his wife is now obligated to do yibum with one of them. We say, “We don't believe him,” since he's changing his wife's halachic status. We assumed beforehand that he had no brothers and she would have been exempt from yibum. Now he's telling us that he has brothers and she's obligated. We do not believe him to change the status of his wife. Therefore, we can make the assumption that he has no brothers, and she would be exempt from yibum.
What happens if a man accepts kiddushin (betrothal) on behalf of his daughter, but they don't specify which daughter he's talking about? Let's say the father went to a man and said, “Give me a perutah (small coin), and I'm going to give you my daughter in marriage.” The man handed over a perutah, and the father said, “Okay, my daughter's married to you now.” So he had a daughter in mind, but it's unknown which daughter he was talking about. The Mishnah says that if a man had more than one daughter and married off a daughter without discussing which one it was, it's unknown which of his daughters is engaged, but one of them is definitely engaged. We say that all of them have to get a get (bill of divorce) if they want to remarry somebody else. But the adult daughters are not included in this doubt. They don't have to get a get because the father wouldn't have the ability to accept kiddushin. So they're not part of the calculation. They're not part of the cheshbon (calculation). Even if a father accepted kiddushin on behalf of his adult daughter, it wouldn't work. Therefore, we don't take them into account when this type of situation arises.