Yun Shifei wasn't against Yun Tiancheng having a new relationship; she just felt that Yun Tiancheng ought to find someone suitable for him, not a woman who was duplicitous.
So, even though Yun Shifei felt that speaking ill of others behind their backs was inappropriate, she still couldn't resist saying it out loud.
To be honest, before coming here, her impression of this woman had been quite good. After all, this was the woman her father liked, and she'd once helped her pick out many beautiful clothes. During their interactions, she had seemed enthusiastic and particularly attentive.
Yun Shifei had developed some goodwill toward her.
Who would have known she'd witness such a scene?
A lot of things can be faked, but those subtle, unintentional details often reveal a person's true character.
At that moment, Yun Shifei's impression of her changed drastically.
Thus, when Yun Tiancheng asked her about it, she hesitated for a moment before deciding to speak up.