TLJ - Elaborates

“Oh?” Snoke asked, radiating mock concern. “Have you seen something? A weakness in my apprentice? Is that why you came?”

He laughed at the dawning horror on her face, and her attempt to hide it. There was nothing she could hide from him—not with her defenses so inadequate. Not even her thoughts—her deepest fears and secrets—were safe from him.

“Young fool,” Snoke said. “It was I who bridged your minds. I stoked Ren’s conflicted soul. I knew he was not strong enough to hide it from you—and you were not smart enough to resist the bait.”

Kylo Ren had remained kneeling in the throne room as Snoke tormented Rey, his face an impassive mask. Now he looked up in surprise, his eyes locked
on his master.

[...]

Snoke laughed. Bridging their minds had been a gamble, one he had weighed for some time. But it had worked even better than Snoke had hoped. It had fooled the girl into revealing Skywalker, but it had also forced Kylo to confront his weaknesses. By eliminating Rey, he would also be excising the flawed, hesitant, weak half of himself.



- The Last Jedi: Expanded Edition, Chapters 25 and 26