Mathilde embraces her new laborious life as the price she must pay. Loisel and Mathilde dismiss their servant and move to cheaper lodgings. Mathilde becomes a common housewife and takes on the heavy housework, committing herself to a life of cleaning, laundry, and bargaining for better prices at local food markets. Loisel begins working in the evenings to bring in extra money. Their life continues on this course for ten years. Finally, after a long and trying decade, the couple is finally able to pay off everything they owe. After ten years of heavy labor, Mathilde has lost much of her beauty and has grown into an old-looking, worn-down woman. She no longer focuses on her appearance and becomes the pinnacle image of the impoverished housewife. She still sometimes fantasizes about her perfect, magical evening at the ball all those years ago and agonizes over how things could have turned out differently had she not lost the necklace and launched herself and her husband into bankruptcy.
One day, she goes for a walk along the river and comes across her old friend, Madame Forestier, who lent her the diamond necklace for the ball all those years ago. Madame Forestier, in all her prosperity and affluence, remains beautiful and youthful. After having finally repaid her debt, Mathilde feels compelled to finally come clean to Madame Forestier and tell her the full truth about the diamond necklace. Mathilde approaches Madame Forestier but due to Mathilde's much-changed appearance, Madame Forestier does not recognize her old friend and is surprised to be approached by a common woman. When Mathilde reveals her identity, Madame Forestier utters a cry, lamenting her former friend's lost beauty.
Mathilde tells Madame Forestier the full truth about the diamond necklace and admits that she lost the original jewels and spent a great fortune to replace it, launching her and her husband into financial ruin. She informs Madame Forestier that they spent the next ten years of their lives paying off the debt. At first, Mathilde is privately proud that Madame Forestier evidently never noticed that her original necklace had been replaced. However, upon hearing the truth about her necklace, Madame Forestier is overcome with emotion and clasps her friend's hands, crying, "My poor Mathilde!" Madame Forestier tells Mathilde that the original necklace was a fake. It was not real diamond and was worth no more than 500 francs. The story ends abruptly with Madame Forestier's startled declaration and ends before we see Mathilde's reaction or what she does with the information.