A good lesson
Yu Dong could see Zi Qian's kindness but she was afraid that Old Master Zi and the rest of the Zi family would try to have designs on Zi Han if she was to let Zi Qian rescue Zi Han. She had seen Old Master Tong's shamelessness and she had also seen Mother Shen's annoying behaviour, she knew that if she did not clear off all the strings then Yu Dong would surely face another round of trouble in the future.
As she did not want to get entangled in another drama. Though she was aware of the fact that Old Master Zi and his family would surely come to look for Zi Mu once they realized that Zi Mu had gotten richer than they could ever become, Yu Dong thought it was better to have a fake slave document to keep these leeches away from sucking Ye Zexian and Zi Mu's blood anymore.