Does a divorce occur with the husband's words "If you were my wife, you would be divorced by three" if he does not know that the speaker is his wife?

The apparent ruling is that divorce occurs with this phrase, whether the husband was serious or joking, if he believed the correspondent was his wife. The divorce is counted as three by the majority of scholars. However, it is possible that no divorce occurs if his intention was that his wife would be divorced if she committed such an act, and then it becomes clear that she did not. It is advised to present the matter to trustworthy scholars.