If we were to go for the politics explanation route, then I at the very least agree that it being “the last night of her training” needs to be replaced with something else. Make it clear that she didn’t train for that long with him.
This is why I had suggested this instead:
Luke: “I started to train her, but Leia was reluctant to follow the Jedi Path. She knew she could better serve the galaxy and its people through diplomacy, like our mother once did. She surrendered her saber to me and said that one day, it would be picked up again by someone who would finish her journey. A thousand generations live in you now. We’ll always be with you, but this is your fight.”