Why?
Despite the trauma of losing both her parents at a young age and being abused by both her stepmother and stepsisters, she remains kind, compassionate and strong completing all her chores with a positive spirit. She finds refuge in fantasy and by dreaming of a better life, she takes great care of those around her who return her favours. She is not even looking for the Prince Charming or for someone to save her, she is waiting for all her dreams to become reality. At the time when she almost lost all hopes after her stepsisters viciously attack her, she materialises a fantasy - the fairy godmother - who washes her tears and make her dream come true: to go to the ball and have a magical experience. At the ball, the prince finds her meandering in the hall and approach her for a dance.
The dance with the Prince gives her an opportunity to dream furthermore about a complete different life made of love and delight.
When she comes back to her home, her stepmother notices her day-dreaming dancing and twirling as she remembers her night. The Stepmother do her best to squash her dream by locking her into her room and stop her spirit shine through and bring forth all her desires. When the Prince helpers come to the house to try the shoes, Cinderella takes action to claim her dream with the help of all her spirited friends - so she can come out of the room and show that she has the glass delicate slipper.
The glass slippers are a reminder that as delicate, fragile our dream can be, as long as we walk in their direction, they will eventually come true.