Responsa for Ketubot 108:6
מתני׳ <big><strong>אף</strong></big> על פי שאמרו בתולה גובה מאתים ואלמנה מנה אם רצה להוסיף אפי' מאה מנה יוסיף נתארמלה או נתגרשה בין מן הארוסין בין מן הנשואין גובה את הכל רבי אלעזר בן עזריה אומר מן הנשואין גובה את הכל מן האירוסין בתולה גובה מאתים ואלמנה מנה שלא כתב לה אלא על מנת לכונסה
Although [the Sages] have said: A virgin collects two hundred and a widow one maneh, if he wishes to add, even a hundred maneh, he may do so. If she was widowed or divorced, either after betrothal or after marriage, she is entitled to collect the entire amount. Rabbi Elazar ben Azaryah says: [a woman widowed or divorced] after marriage receives the entire amount; After betrothal [but before marriage], a virgin collects two hundred zuz and a widow only one maneh, for the man wrote her [the additional amount] in order to marry her.
Teshuvot Maharam
A. A dowry gift becomes the property of the donee only if the marriage takes place. Therefore, neither A nor his daughter has ever gained title to B's money, and A must return the principal plus the interest to B. Even if B expressly stipulated that he will forfeit the 15 pounds if the marriage does not take place, such a stipulation is considered an Asmakhta and is not valid. B, however, must pay A for his trouble in managing B's investments.
SOURCES: Cr. 86; Pr. 285; Mord. B.B. 615; Agudah B.B. 198.
Teshuvot Maharam
A. A dowry gift becomes the property of the donee only if the marriage takes place. Therefore, neither A nor his daughter has ever gained title to B's money, and A must return the principal plus the interest to B. Even if B expressly stipulated that he will forfeit the 15 pounds if the marriage does not take place, such a stipulation is considered an Asmakhta and is not valid. B, however, must pay A for his trouble in managing B's investments.
SOURCES: Cr. 86; Pr. 285; Mord. B.B. 615; Agudah B.B. 198.