Cosette is a good character. Except for one circumstance, she does not cause any harm towards others. Her and Marius' love was an unintentional stab in the back to Eponine. Cosette grows up to be a good person, someone any mother would have been proud of. She introduces love into Jean Valjean's life and he becomes a loving, kindhearted father to her. Like all fathers, Jean Valjean was hesistant and stubborn about letting Cosette go to be with the love of her life. But he soon realizes that if he doesn't bring Marius home safe to Cosette, then she will have no one when Jean Valjean is dead and gone.
Cosette represents love throughout the whole movie. Even though, for a while, she is a lonely person hiding away with Jean Valjean, she is still kind to him and comforts him. When she finds Marius, she finds a new kind of love she has never been introduced to. Cosette shows both a romantic kind of love and a family kind of love.