Reference for Ketubot 2:5
הָאִשָּׁה שֶׁאָמְרָה אֵשֶׁת אִישׁ הָיִיתִי וּגְרוּשָׁה אָנִי, נֶאֱמֶנֶת, שֶׁהַפֶּה שֶׁאָסַר הוּא הַפֶּה שֶׁהִתִּיר. וְאִם יֵשׁ עֵדִים שֶׁהָיְתָה אֵשֶׁת אִישׁ וְהִיא אוֹמֶרֶת גְּרוּשָׁה אָנִי, אֵינָהּ נֶאֱמֶנֶת. אָמְרָה נִשְׁבֵּיתִי וּטְהוֹרָה אָנִי, נֶאֱמֶנֶת, שֶׁהַפֶּה שֶׁאָסַר הוּא הַפֶּה שֶׁהִתִּיר. וְאִם יֵשׁ עֵדִים שֶׁנִּשְׁבֵּית וְהִיא אוֹמֶרֶת טְהוֹרָה אָנִי, אֵינָהּ נֶאֱמֶנֶת. וְאִם מִשֶּׁנִּשֵּׂאת בָּאוּ עֵדִים, הֲרֵי זוֹ לֹא תֵצֵא:
If a woman says: I was married, but I was divorced, she is believed, for "the mouth that forbids is the mouth that permits." And if there are witnesses that she was married, and she says: I was divorced, she is not believed. If she said: I was taken captive, but I am clean (i.e., I was not forced), she is believed (to marry a Cohein), for "the mouth that forbids is the mouth that permits." And if there are witnesses that she was taken captive, and she says: I am clean, she is not believed. And if after she were married witnesses came, she does not leave. [Not that she had actually been married; but if after she had been permitted to marry, witnesses came and testified that she had been abducted, she does not "leave" her first license and she may marry ab initio. But if witnesses came that she had been defiled, even if she had several children, she leaves.]