What does the Gemara mean by שֶׁמְּמָאֲנִין אֶת הַקְּטַנָּה?

Question

Brachot, Perek 4, daf 27, amud A, says

רִבִּי יְהוּדָה בֶּן בָּבָא הֵעִיד חֲמִשָּׁה דְּבָרִים שֶׁמְּמָאֲנִין אֶת הַקְּטַנָּה וְשֶׁמַּשִּׂיאִין אֶת הָאִשָּׁה עַל פִּי עֵד אֶחָד וְעַל תַּרְנְגוֹל שֶׁנִּסְקַל בִּירוּשָׁלַיִם עַל שֶׁהָרַג אֶת הַנֶּפֶשׁ וְעַל יַיִן בֶּן אַרְבָּעִים יוֹם שֶׁנִּתְנַסֵּךְ עַל גַּבֵּי הַמִּזְבֵּחַ וְעַל תָּמִיד שֶׁל שַׁחַר שֶׁקָרֵב בְּאַרְבַּע שָׁעוֹת

Rabbi Yehuda ben Bava testified on five things: That they instruct a minor girl to refuse, that we may remarry a woman on the word of one witness that her husband is dead, that a chicken was stoned in Yerushalayim because it killed a person, That forty-day old wine was poured as a libation on the altar, and that the morning daily offering was once brought at four hours.

What does the Gemara mean when it says "שֶׁמְּמָאֲנִין אֶת הַקְּטַנָּה"? I know Rashi explains but I tried read the Rashi but I could not understand it.

Answer 1

Sefaria offers a fairly comprehensive translation of most of Gemara which you might find helpful. They translate this line of the Gemara as "When an orphan girl, who was married off by her mother or brother before reaching the age of majority, reaches the age of majority, she may refuse to continue living with her husband and thereby retroactively annul their marriage. Normally, marriage refusals are discouraged. However, in specific instances where it is clear that if the marriage were to remain in effect it would engender problems related to levirate marriage and ḥalitza, Rabbi Yehuda ben Bava testified that one may persuade the minor girl to refuse to continue living with her husband, thereby resolving the complications involved in this case."

Also, if you're interested in understanding that Rashi, Mercava translates each Rashi line by line. Just click on the Rashi and it'll highlight the line as well as the translation on the bottom.