Lavender-Nuy
Wei Wuxian is a feared loan shark from whom Lan Qiren had once borrowed a huge amount of money and hadn't paid back yet. It's been years and Wuxian was done reminding the other to pay, so he decided to threaten Lan Qiren.
"If you don't pay back, I'll marry your son forcefully."
But Wuxian didn't know why... he had expected Qiren to shiver in fear and pay him back asap, but Lan Qiren seemed to loose his interest (if he had any) in clearing his debt.