And if we want to retain Palpatine wanting to kill Rey (which fits better with TFA/TLJ):
“You know why the Emperor wanted to kill you. I’ll come tell you.”
“Why did the Emperor want to kill me?”
“Because he only needed one vessel from the two dark bloodlines he sired. Vader’s, or the one he perfected with you. You… are Palpatine’s heir.”
"We were created to inherit the legacy of the Sith. Skywalker and Palpatine. But what he doesn’t know is that we’ve become a dyad in the Force, Rey… two, linked by raw power. We can end him and the Sith, and create something new, together…”
(Removes his helmet)
“You know what you need to do. You know.”
“I do.”