Here's why it's hard to say for sure:
* Fairy Tales Don't Often Mention Personal Preferences: Cinderella's stories focus on her struggles, kindness, and ultimately, finding love. Her favorite color isn't a critical plot point.
* Different Adaptations Have Different Details: Each version of Cinderella may have slightly different details. Some might mention her favorite color, while others might not.
So, while we can't be certain, Cinderella's love for blue is a popular and charming detail, making it a strong contender for her favorite color!