What is the ruling on one who swore to divorce his wife using the phrase: "By Allah, if you enroll in the university, you will not return to my house," and then said: "Three divorces, not just one divorce." Does the divorce take effect if she enrolls in the university, knowing that he actually intended divorce, and is reconciliation possible if the divorce takes effect?

If you intended to effect a divorce when your wife enrolled in the university, then she is divorced upon her enrollment. According to the majority of scholars, a triple divorce takes place, and your wife becomes irrevocably divorced from you (baynunah kubra). You cannot remarry her unless she marries someone else, he consummates the marriage with her, and then he divorces her or dies, and her waiting period (iddah) expires. Some scholars, like Ibn Taymiyyah, hold the view that only one divorce occurs, and according to this opinion, you can take your wife back during her waiting period.