Because Long Dan's wife can't afford these real jewels anyway, they must have been given by others. As for why others will give Long Dan's wife such precious jewels, the reason is self-evident.
After betraying her husband, in order to cover up the truth, she can only lie and tell her husband that these jewels are fake, and then enjoy the joy brought by these jewels aboveboard. If she had not died suddenly, her husband would not have known the truth.
Extended data
Introduction of main characters:
1, Mrs. Langdan
Langdan's dead wife had two hobbies before her death: love of the theatre and fake jewelry. These two hobbies themselves illustrate her inner emptiness and vanity. What's more, the satisfaction of her hobby of "loving fake jewelry" is actually conditional on selling her color.
After betraying her sex and personality, she not only did not feel any guilt and pain, but also appeared unusually "happy" in front of her husband, which shows how much Mindan's wife's morality has deteriorated.
2. Langdan
After Langdan accidentally discovered that the "fake jewels" of his dead wife turned out to be expensive real jewels, especially when he decided that these jewels were "gifts" given to his dead wife by others, he only felt "doubt", "sadness" and humiliation for a short time.
However, one night later, in order to get the "happiness" of "owning property", he finally couldn't resist the temptation of "owning money", exchanged the jewelry symbolizing shame for a large sum of money, and immediately began to splurge.
When boasting to the section chief and a complete gentleman, the number of francs began to swell. In a word, vanity and wealth are the core of Lang Dan's character, and the main motivation for forming this character is the temptation of money and the resulting degradation of human nature.
Baidu Encyclopedia-Jewelry (a short story written by Mo Bosang)