How sure should I be before making a lifelong commitment like marriage?

It's like getting married. You don't get engaged to somebody saying, "I'm 85 percent sure I want to marry them," with 15 percent that still has to be worked out. You don't show up on your wedding day and say, "We're most likely going to stay married." That's not how we enter into things that are lifelong commitments. When we get engaged to somebody, we should know: this is the person I want to live the rest of my life with. On the day of our marriage, we should know: this is the person I am committed to for the rest of my life.