What is the legal ruling, and what is the advice on how to deal with a wife who harms her husband's daughter? Is divorce permissible due to the harm inflicted upon the daughter, especially when there is a child between the spouses?

Efforts should be made to instill the meanings of love, mercy, and compassion in the wife's heart. If this does not succeed, then the husband has no option but divorce. It is not advisable to be harsh with her, as this might increase her harm towards the daughter.