* They give her impossible tasks: The stepmother and stepsisters force Cinderella to do endless chores, like cleaning the house, washing clothes, and preparing meals. They overload her with work to keep her busy and ensure she can't get ready for the ball.
* They mock and belittle her: They constantly criticize Cinderella's appearance and make fun of her for being poor and plain. They try to make her feel inferior and discourage her from even thinking about going to the ball.
* They try to ruin her dress: The stepsisters purposely tear Cinderella's dress as she is trying to get ready, making it seem impossible for her to go.
* They lock her in her room: To ensure she doesn't escape, they physically lock Cinderella in her room, preventing her from attending the ball.
All of these actions are fueled by their jealousy and desire to have all the attention and beauty at the ball themselves. They want to be the center of attention and fear that Cinderella's presence will detract from their own.