Throughout ROCH novel it was consistently shown that HR dislikes YG, she has always thought the worst of him. For example, she thought YG was evil like his father and teaching him martial arts would lead to him harming/killing her family, she also thought that he took her baby daughter to try and exchange for the antidote and why she agreed that Guo Fu slicing off his arm was the right thing to do, HR even said that if it was her she would have sliced his remaining arm. Even in the latter parts of the novel, when Yang Guo have saved her family members again and committed good deeds for Xiangyang, she still didn't want Guo Xiang around YG, believing that if he didn't meet XLN again that he would go crazy and harm her youngest daughter. Furthermore, HR believes that YG's relationship with XLN was the equivalent of incest and no different than what animals do (it was in either the 1st or 2nd edition that she thought this way, forgot which one).
With the examples I have listed, it has been established throughout the novel that HR does not like YG and she thinks he is a despicable character capable of doing the most immoral things. So then why did she make up the story of the divine nun of the south seas to try and comfort Yang Guo during his most painful point in life? Wouldn't HR not give a damn and even revel in YG's pain?