Reference for Kiddushin 18:2

בתר דבעיא הדר פשטה הוייה ליציאה מקשינן דאמר קרא (דברים כד, ב) ויצאה והיתה :

so betrothal by deed need not be for her sake? - After putting the question he, himself, decided it: betrothal is assimilated to divorce, for Scripture writes, and when she is departed [i.e., divorced]. she may be [another man's wife].<span class="x" onmousemove="('comment',' Thus, betrothal and divorce are stated in proximity to each other, shewing that they are compared.');">³</span>

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