In his poem "Ode on a Grecian Urn," John Keats pronounced that "beauty is truth, truth beauty." While subsequent generations have appreciated this Romantic assertion, Maupassant's story aptly demonstrates that it is not always correct. Madame Loisel is beautiful, but she is not content. She has the appearance of beauty but not the reality (or truth) of beauty. She is pretty and charming, but she is also unhappy with her lot in life and believes that she deserves more. Living modestly with her husband before the ball, Madame Loisel believes she is suffering a terrible injustice by having few luxuries. In fact, she does not experience the reality of poverty until she and her husband go into debt to pay off the necklace. The necklace itself represents the theme of appearances versus reality. While sufficiently beautiful to make Madame Loisel feel comfortable during the ministerial ball, the necklace is actually nothing more than paste and gilt. Thus, it is not the reality of wealth or high social class that is important for Madame Loisel, just the appearance of it.
In context, it is my opinion that Mathilde represents the idea that women are weak, whiny, and selfish. She marries her husband but is not happy, she consistently nags him for more, and she is unappreciative of the many things she has... one being a comfortable life and aspires to those things she cannot have.
Mathilde wants the best, and yet, she is herself unable to distinguish between what is real and what is fake. She makes assumptions rather than thinks things through, and she is too prideful or childish to admit when she has made a mistake. We have to give her credit, however, when she actively takes part in working off the debt... something that has always surprised me. In the end, however, she once again disappoints me when she approaches Madame Forestier and chooses that time to tell her the truth. Her confession doesn't seem so much a moment of redemption, as it does an excuse for her own appearance and circumstances, and she never truly takes responsibility, but lays the blame at her friend's feet.
Her friend uttered a cry. "Oh! . . . my poor Mathilde, how you have changed! . . ."
"Yes, I've had some hard times since I saw you last; and many sorrows . . . and all on your account."