I really don’t want to mess around with lines spoken on screen. But I do believe somebody mentioned “Because you’re from Palpatine?”

Or we could get a take of him saying that sentence which sounds a little less serious and more of a “Really? Are you serious?” kind of tone. As in, you seriously bought into that crap? Because I do think the line as it stands could work in that way, where he’s only stating what Rey was unable to say herself: “I’m afraid of myself because I believe I’m a Palpatine.” But by the end of the movie she knows she isn’t one by claiming she’s a Skywalker.

Alternatively, we can forgo the whole Leia knowing something about Rey part so we are free to put whatever line we want immediately after that. Something like, “Because you’re a Palpatine? The Force alone made us, light and dark.”