An 'error of destiny' is the belief that one is meant for a different type of life and does not have control over one's life, or is unable to correct the circumstances of one's life.
Matilda was born and married into a poor family. She desired a life of luxury. There were constant conflicts with her husband as a result of her craving for a life beyond her means.
She borrowed a necklace from a friend to show off her purported status to others and ended up losing it. Then she and her husband spent the next ten years trying to repay the debt, which put them through greater hardship.
Matilda's belief also made her constantly compare her life with her rich friends, and put pressure on her simple and hardworking husband.
