[Bonus chapter] Not fair to her
Yu Dong said nothing she understood Fang Chi's feelings and she understood Mu Yuxi's feelings as well. Making a rebellious promise as a teenager was something every teenager did, however, once they mature they realise that their rebellion phase was nothing but stupidity on their part. Most likely Mu Yuxi realised it too, she might have liked Fang Chi as a teen but once she became an adult she understood her mother's feelings for not letting her get along with Fang Chi.