Yes, the DOTF dialogue is as follows:

Luke: “This is why the Jedi live in isolation. The pain of loss only leads to the dark side.”
Leia: “I’ve lost everything, and everyone. But I’d still choose to love.”

As for the whole Leia knowing thing, we can certainly keep giving that more thought. I believe the last line we left off with was:

“Because you’re a Palpatine. Leia sensed his power in you.”

But, yeah, this doesn’t effectively convey that it was something that happened between episodes 8 and 9. Off the top of my head, the next best thing would be “Leia sensed his power as she trained you.”