What he did to CZ in her 2nd rebirth that she hates him so much
LYF was shocked! I guess he didn't have the intention of saving a piece of her soul so that she can rebirth again when he killed her. Mu shishu and WY wasn't surprised since they knew (cos they were the ones that planned everything!) As for that Qinghua boy and YK, they were shocked, in a good way I guess. In the novel, CBF, Mu shishu and Shi xiong all died for her. It was very sad.
What he did to CZ in her 2nd rebirth that she hates him so much
They did. LYF killed himself in order to grant her forgiveness and be with her after he realised he loved her and cannot lose her. Both lived inside the sword afterwards. It took her 100 years to finally forgive him.
What he did to CZ in her 2nd rebirth that she hates him so much
He tortured her, abused her trust and love to hurt her again and again. Like what CZ said, what did she do to deserve all the unfairness and treatment? I second that. She was such a kind girl. It was LYF and all the self righteous people that pushed her to became 'bad'. He truly doesn't deserve any forgiveness and I'm glad that CZ did not grant him any.
He killed her once in this lifetime. Second lifetime, tortured her, hurt her, abused her trust and love again and again. It's heartbreaking for Chong Zi.