PeachBlossomGoddess:
I think the ending was as complete as it needs to be. In brief, Weishan was not fooled, she went back to Wufeng bc she still needs to take revenge on Dianzhu for Zhuomei. Its in more detail at the bottom of my review.
It just dawned on me that Weishan promised Ziyu she'd be back in a couple of days, so she couldn't have planned to go back to Wufeng. If she had wanted to, she could've asked for freedom to leave, Ziyu was willing (albeit reluctantly) to give it to her. And according to the letter, she's a twin from the Yun family, which suggest she's not Zhuomei's daughter. I'm still curious about her connection to Zhuomei, but Weishan only talks about Zhuomei when she has to explain her wugong, otherwise she doesn't seem to have deeper connection with her. Weishan also doesn't express any revenge intention throughout the drama, even when she suspected Yun Que died at the hand of the Gong family, she never intended to avenge her in any way, so that'd be so out of character.
As for the last scene, I interpreted Ziyu's look as someone who was disappointed, meaning whoever showed up in front of him was not Weishan. It could be just Jin Fan. ?♀️