How does Mathilde Loisel's motivation change during the course of the story "The Necklace".

Mathilde Loisel is the main character in Guy de Maupassant's short story "The Necklace." At the beginning of the story she is described as unhappy and bored with her middle class life. She longs for the material trappings of the upper class. She takes for granted her devoted husband and comfortable, if not lavish, lifestyle. After all, she even has a maid. These things are not enough for her, however, and she dreams of wealth,...

Mathilde Loisel is the main character in Guy de Maupassant's short story "The Necklace." At the beginning of the story she is described as unhappy and bored with her middle class life. She longs for the material trappings of the upper class. She takes for granted her devoted husband and comfortable, if not lavish, lifestyle. After all, she even has a maid. These things are not enough for her, however, and she dreams of wealth, luxury and being around important people. De Maupassant writes,

She would dream of great reception halls hung with old silks, of fine furniture filled with priceless curios, and of small, stylish, scented sitting rooms just right for the four o’clock chat with intimate friends, with distinguished and sought-after men whose attention every woman envies and longs to attract. 

Even when her husband brings home an invitation to a fancy ball she is not satisfied until she has a new dress and expensive jewelry to wear. Her motivation is totally materialistic in the beginning. That is, until she loses the necklace she borrowed from her friend Madame Forestier.

Because of the loss, and the stifling social etiquette of the time which prevented her and her husband from telling Madame Forestier, they purchase, for a hefty price, a replacement. The expenditure throws the couple into poverty and that is when Mathilde's motivation changes. Instead of wallowing in sorrow she behaves quite admirably by helping her husband pay off the debt. She rises to the occasion:

Mme. Loisel experienced the horrible life the needy live. She played her part, however, with sudden heroism. That frightful debt had to be paid. She would pay it. She dismissed her maid; they rented a garret under the eaves. 

By changing significantly and altering her motivation she becomes a dynamic character that the reader might almost admire if we didn't feel very sorry for her as she learns, in a surprise twist, that the necklace was actually worth nothing.