"The Necklace" is probably the most famous short story ever written in any language. It would be hard to think of a story that is better known and more frequently anthologized. Guy de Maupassant had to solve many plot problems in writing it. One problem was how to explain how Loisel managed to pay for a diamond necklace which he previously could never have dreamed of buying for his wife. Characteristically, Maupassant gets through with his explanation quickly, because a longer explanation would only raise more doubts and more questions in the reader's mind.
First the Loisels had to find a necklace that would match the one that had been lost on the night of the evening reception at the ministerial mansion. This was obviously difficult, since diamond necklaces would all be custom-designed. A woman who could own such a necklace would want it to be unique. That was another plot problem. But the Loisels find a necklace that will pass. The jeweler wants thirty-six thousand francs for it. Now we learn that M. Loisel, fortuitously, has eighteen thousand francs inherited from his father. He would have to borrow eighteen thousand more. Maupassant explains how this is done in one transitional paragraph.
He went about raising the money, asking a thousand francs from one, four hundred from another, a hundred here, sixty there. He signed notes, made ruinous deals, did business with loan sharks, ran the whole gamut of moneylenders. He compromised the rest of his life, risked his signature without knowing if he'd be able to honor it, and then, terrified by the outlook for the future, by the blackness of despair about to close around him, by the prospect of all the privations of the body and tortures of the spirit, he went to claim the new necklace with the thirty-six thousand francs which he placed on the counter of the shopkeeper.
It is hard to tell how much thirty-six thousand French francs in the mid-nineteenth century would be worth in current American dollars, because of the intervention of two world wars and numerous other calamities, but a diamond necklace such as Maupassant describes in his story would cost at least $150,000 today. And thus he would have borrowed something like the equivalent of $75,000. It would have been hard enough to pay back the principal--but he had committed himself to paying "ruinous" interest on a large part of the borrowed money--possibly something like twenty percent per annum. So by the time the Loisels finally got the necklace paid off, they would have had to pay the equivalent of, let us say, $150,000. And Loisel was only earning enough to cover his and his wife's living expenses from month to month. If they had ever thought of having a baby, they would have had to give it up along with everything else they sacrificed.
The reader may well wonder why Mme. Loisel didn't just go to Mme. Forestier and tell her she was awfully sorry but she had lost the diamond necklace she had borrowed. This is a question Maupassant simply neglects to deal with.