The members of the Lin family are not as naive as Lin Qinghan; Tingzheng was raised by Lian Yueyao. If Lian Yueyao truly decided to make Tingzheng divorce his wife, Tingzheng wouldn't dare defy her. At that point, there would be no chance for redemption. Unfortunately, Lin Qinghan adamantly refused to agree, leaving everyone in the Lin family thinking she's gone mad.
Wanting accidentally overheard Lady Lin and Lin Qinghan's argument, and found out that Yueyao wanted her father to divorce her mother. She was dumbfounded at the time. Wanting wasn't clear about Yueyao's affairs; apart from knowing she had such an aunt, she knew nothing else.
Wanting's personal maid's parents were family-born servants of the Lian family, and they knew relatively more. It was through her personal maid that Wanting learned that Yueyao's identity was not simply her father's biological sister.
