What does the Dragon King mean by recruiting a son-in-law?

The dragon king's intention to recruit a son-in-law is to say that the other person is a turtle in a humorous tone.

The wife of the Dragon King is a very humorous story. It means to say that the other person is a turtle in a joking tone, because the end of the story is to tell a story to the turtle, and you are the one who listens to the story. The legend of the story is that there was a dragon king who watched his daughter grow bigger and bigger, and when it was time to get married, he began to prepare to find a husband for her.

In a short time, the news that the Dragon King recruited a son-in-law spread at sea. Many beasts and elves in the sea signed up immediately after hearing the news. After layers of selection, the tortoise stood out, but at the last level, the tortoise was puzzling. The dragon king asked his son-in-law to be over 90 years old, and the tortoise was only 89 pounds, so the tortoise had to leave sadly.

When the two crawfish on the road heard what happened to the tortoise, they couldn't help feeling sorry for it. They said to the tortoise, we are half a catty of shrimp and a catty of shrimp. Let's hide in your ear and weigh together. The tortoise went back and weighed it again, which was exactly 90 Jin. The dragon king met the tortoise and asked him, why did you suddenly gain a kilo? The tortoise was so nervous that he dropped two crayfish. The dragon king met crayfish and asked them, What are you doing? The crayfish said, I am telling a story to the tortoise.