What is the Shar'i ruling if a wife swears that she will be unlawful to her husband if she speaks to so-and-so, and then circumstances compel her to speak with her?

A wife does not have the right to divorce her husband, for the knot of marriage is in the husband's hand. The wife does not become unlawful to her husband by saying to him: "You are to me as the back of my father," but she is required to pay expiation for ẓihār because she uttered an abominable and false statement. The expiation for ẓihār is to free a slave; if she cannot find one, then to fast for two consecutive months; if she cannot do that, then to feed sixty needy persons. She must also repent to Allah and not repeat such a statement.