Positive commandment · Mitzvat Aseh #218 of 613
For a rapist to marry the woman he raped
לישא אונס
The verse · Devarim 22:29
וְנָתַן הָאִישׁ הַשֹּׁכֵב עִמָּהּ לַאֲבִי הַנַּעֲרָ חֲמִשִּׁים כָּסֶף וְלוֹ־תִהְיֶה לְאִשָּׁה תַּחַת אֲשֶׁר עִנָּהּ לֹא־יוּכַל שַׁלְּחָהּ כׇּל־יָמָיו
“then the man that lay with her shall give to the girl’s father fifty shekels of silver, and she shall be his wife; because he has humbled her, he may not put her away all his days.”
The Rambam’s words
For a rapist to marry the woman he raped, as [Deuteronomy 22:29] states: "She shall become his wife."
לישא אונס שנאמר: "ולו תהיה לאישה" (דברים כב,כט).
Why · Sefer HaChinuch #557
The commandment on the rapist to marry the one he has raped
“It is from the roots of this commandment [that it is] in order to restrain the villains from this evil deed, and that the daughters of Israel should not be as if abandoned.”
Who & when
“And this commandment is practiced with regard to forcing payment of the fine by males during the time of the Temple, when there is the power in our hands to adjudicate the laws of fines; but with regard to the rapist marrying her, even in our times it is a commandment upon him — as the marriage is a commandment and not a fine.”
Where in the Mishneh Torah
Hilchot Virgin Maiden הלכות נערה בתולה