For the sake of argument, lets assume that Cinderella’s feet looked like those of a normal young woman. If that is the case, the only way her foot would be different than the other subjects of her country would be if they were extremely large or extremely small.
There is correlation between foot size and height. For her feet to be at either extreme, Cinderella would be either quite short or quite tall. Short or tall enough that she would look mismatched with a regular sized monarch. Short or tall enough that a huge search of the kingdom would be very short lived.
No, Cinderella must have had odd feet in another way.
Some of you are already thinking like me that corns, bunions, warts or pimples might have made her glass slipper unique in the kingdom. But most of these afflictions turn men away from the pursuit of the afflicted women. That is usually one of the reasons women try to rid themselves of these problems. There is, however, a possibility the prince had a fetish for one of these conditions. To avoid the question of why this is, we will simply ignore that possibility.
Perhaps she had an odd number of toes. That would make her feet unique. But in many superstitious olden times, an extra digit or three could lead to being burned alive.
Perhaps her stepsisters had cruelly cut off one of her toes. But that would likely lead to Cinderella seeking the king’s justice which would have likely led her to having already met the prince.
The only other way I can think of for Cinderella’s feet and the glass slipper to be oddly shaped was that she was in dire need of orthotics. Which would mean that the cruelty of her step sisters and step mother would have been magnified by having to perform hard labour with ill prepared feet.
Then when Cinderella was given the correcting, orthotic glass slipper, smiles must have come easy to her that night. At last, dancing would have been a breeze and something she suddenly greatly enjoyed. All of which helped bewitch the prince.
Yes, yes. Cinderella’s glass slippers must have been orthotics, specially made for just her feet.