Why don’t I remember that line? But honestly…
“I’m never leaving this place. I’m doing what you di-”
“I was wrong. [beat] Lesson Three [Rey looks up] What are you most afraid of?”That would be really good. Ties up a loose end from TLJ too, and creates a bonus through line between the two films.
If you were going to imply this was her third lesson, I think you also could word it like, “Lesson Three: Confronting fear is the destiny of a Jedi. Your destiny…” But that makes sense too, like he is beginning her third lesson.
Either one of these would work solidly.