The Mishnah establishes the distinctive, more flexible evidentiary framework for testimony that a woman's husband died, while carefully defining when such testimony is sufficient for remarriage.
הָאִשָּׁה שֶׁהָלְכָה הִיא וּבַעְלָהּ לִמְדִינַת הַיָּם, שָׁלוֹם בֵּינוֹ לְבֵינָהּ וְשָׁלוֹם בָּעוֹלָם, וּבָאתָה וְאָמְרָה, מֵת בַּעְלִי, תִּנָּשֵׂא. מֵת בַּעְלִי, תִּתְיַבֵּם. שָׁלוֹם בֵּינוֹ לְבֵינָהּ וּמִלְחָמָה בָעוֹלָם, קְטָטָה בֵינוֹ לְבֵינָהּ וְשָׁלוֹם בָּעוֹלָם, וּבָאתָה וְאָמְרָה, מֵת בַּעְלִי, אֵינָהּ נֶאֱמֶנֶת. רַבִּי יְהוּדָה אוֹמֵר, לְעוֹלָם אֵינָהּ נֶאֱמֶנֶת, אֶלָּא אִם כֵּן בָּאתָה בוֹכָה וּבְגָדֶיהָ קְרוּעִין. אָמְרוּ לוֹ, אַחַת זוֹ וְאַחַת זוֹ, תִּנָּשֵׂא: בֵּית הִלֵּל אוֹמְרִים, לֹא שָׁמַעְנוּ אֶלָּא בְּבָאָה מִן הַקָּצִיר, וּבְאוֹתָהּ מְדִינָה, וּכְמַעֲשֶׂה שֶׁהָיָה. אָמְרוּ לָהֶן בֵּית שַׁמַּאי, אַחַת הַבָּאָה מִן הַקָּצִיר, וְאַחַת הַבָּאָה מִן הַזֵּיתִים, וְאַחַת הַבָּאָה מִן הַבָּצִיר, וְאַחַת הַבָּאָה מִמְּדִינָה לִמְדִינָה. לֹא דִבְּרוּ חֲכָמִים בַּקָּצִיר אֶלָּא בַהֹוֶה. חָזְרוּ בֵית הִלֵּל לְהוֹרוֹת כְּבֵית שַׁמָּאי:
With regard to a woman who went, she and her husband, overseas, if there was peace between him and her, i.e., the couple were not fighting at the time, and there was also peace in the world, i.e., there was no war at that time, and the woman came back by herself and said: My husband died, she may marry on the basis of her own testimony. Likewise, if she said: My husband died, and they did not have children, but her husband had a brother, she may enter into levirate marriage. If there was peace between him and her when they left but there was war in the world, or if there was a quarrel between him and her and peace in the world, and she came and said: My husband died, she is not deemed credible, as she may be mistaken or lying. Rabbi Yehuda says: She is never deemed credible when she testifies that her husband died, unless she came crying and her clothing was torn, in which case it is apparent that she is speaking the truth. They said to him: This is an incorrect distinction. Rather, both this woman who cries and this woman who does not cry may marry on the basis of their own testimony. Beit Hillel say: We heard that one may accept the testimony of a woman concerning the death of her husband only when she comes from the grain harvest, and when she testified in the same country where he died, and in circumstances similar to the incident that occurred, in which a lenient ruling was issued, as will be explained. Beit Shammai said to Beit Hillel: The same halakha applies to a wife who comes from the grain harvest, and one who comes from the olive harvest, and also one who comes from the grape harvest, and even one who comes from one country to another country. Although the incident in question took place during the grain harvest, the Sages spoke of the grain harvest only because it was the present occurrence, i.e., that is what happened in practice, but this is no proof that she is deemed credible only when she arrived specifically from the grain harvest. The mishna comments: Beit Hillel retracted their opinion, and decided to teach in accordance with the opinion of Beit Shammai on this issue.