Answer:
The Prince would marry one of Cinderella's sisters.
Step-by-step explanation:
Because in the fairy tale one of the sisters, Anastasia tried to shove her foot in the glass slipper without knowing it would not fit, so she forced it to when it did not work. So, if the Prince did not find the rightful owner of the glass slipper by the next day, he would most likely marry one of Cinderella's step sisters, most likely Anastasia.
So sorry if I am incorrect :,(