Jaq: Lucify. That's him. Meany, sneaky. Jump at you. Bite at you.
Cinderella: Why, it's my.
Mice and Birds: Surprise! Surprise! Surprise.
Gus: Duh, duh, duh... Happy Birthday.
Jaq: No, no, no, no.
Cinderella: Oh, well. What's a royal ball? After all, I suppose it would be frightfully dull, and-and-and boring, and-and completely... Completely wonderful.
Cinderella: Why, it's like a dream. A wonderful dream come true.
Fairy Godmother: Yes, my child, but like all dreams, well, I'm afraid this can't last forever. You'll have only 'til midnight, and then.
Cinderella: Midnight? Oh, thank you.
Fairy Godmother: Oh, now, now, now, now, now, just a minute. You must understand, my dear: On the stroke of twelve, the spell will be broken, and everything will be as it was before.
Cinderella: Oh, I understand, but... it's more than I ever hoped for.
Cinderella: It's midnight.
Prince Charming: Yes, so it is. But, why.
Cinderella: Goodbye.
Prince Charming: No, no, wait. You can't go now. It's only.
Cinderella: Oh, I must, please. Please, I must.
Prince Charming: But, why?
Cinderella: Well, I-I, oh, the Prince. I haven't met the Prince.
Prince Charming: The Prince? But, didn't you know that.
Answer: Cinderella's entire outfit was magically created by the Fairy Godmother. Not only was the spare shoe Cinderella had in her possession identical to the other one, it likely would be charmed so that she is the only one who can wear it. It's similar to young Arthur being the only person who could pull Excalibur from the stone because he was the true king. No other woman who attended the ball wore glass slippers. If they had, they'd be able to also produce the spare shoe as proof.
raywest ★