From Shmoop and Sparknotes
The Surprise Ending and Irony
“The Necklace” is most famous for its “whip-crack” or “O. Henry” ending. O. Henry, who wrote during the late 1800s, was famous for his twist endings that turned stories on their heads. In “The Necklace,” the surprise ending unhinges the previously implied premise of the story. Until this point, the reader has been able to interpret Mathilde’s ten years of poverty as penance for her stolen night of pleasure at the party and for carelessly losing the borrowed necklace. The ending shatters that illusion, revealing that the ten years of misery were unnecessary and could have been avoided if only Mathilde had been honest with Madame Forestier. Losing the necklace had seemed to be Mathilde’s fatal mistake, but it was actually Mathilde’s failure to be truthful with Madame Forestier that sealed her fate. This shocking realization sheds new light on the previous events and suggests that Mathilde’s future—even though her debts are now repaid—will be none too rosy.
The horrible irony of the fact that the Loisels spent years paying off a replacement for what was actually a worthless necklace is just one instance of irony evident in “The Necklace.” Also ironic is the fact that Mathilde’s beauty, which had been her only valued asset, disappears as a result of her labor for the necklace. She had borrowed the necklace to be seen as more beautiful and winds up losing her looks completely. Perhaps the most bitter irony of “The Necklace” is that the arduous life that Mathilde must assume after losing the necklace makes her old life—the one she resented so fully—seem luxurious. She borrows Madame Forestier’s necklace to give the appearance of having more money than she really does, only to then lose what she does have. She pays doubly, with her money and looks, for something that had no value to begin with.
The ending to "The Necklace" may just be the mother of all twist endings. But just how does it work? What makes it a "twist ending?" The short answer: the twist ending depends upon suddenly revealing some bit of completely unexpected but hugely important information right at the close of the story. Somehow, that bit of information radically changes the meaning of what came before it. Why don't we have a closer look to see how the twist plays out in the story.
Mathilde's problem is that she accidentally loses something expensive and has to replace it. It seems sad, and maybe a little pointless, that her whole life is ruined on account of one little necklace, but what else can she do? She's got to make up for the valuable thing she lost. And so her ten years of hard work, her poverty seems kind of necessary: it has a purpose, and we admire the way she slogs through it all. Mathilde's experience of suffering appears to have helped her grow, and it's given her something to be proud of. And now she's ready to move on. When she meets Mme. Forestier on the street, all she has to do is come clean about substituting the necklace, and that whole episode of her life will be over. It looks like the ending will leave us feeling resolved and optimistic, even if it's not exactly a "happy" one.
But then Mme. Forestier reveal that the necklace Mathilde lost was a fake. That's totally unexpected and it changes the situation completely. If Mathilde and M. Loisel had just known the real value of the necklace – or if they'd just told Mme. Forestier what about what happened –they could have paid for it easily, without any debt. This whole time they thought that they were suffering necessarily, for a reason, they were actually suffering needlessly. By the way, revealing that contradiction between what the characters think about their situation, and what their situation actually is, technically makes this a moment of irony. Irony's often an ingredient of the best twist endings.
Mathilde's suffering, in other words, is now revealed to be pointless suffering (and...