[That's a rather large snag, in Rey's opinion.]

You believe it's there, because Lark said it was.

[She makes that correction as delicately as she can, but it's the entire goal of this plot of his and it's something they need to be more sure of.]

Who did he follow? Can he describe what he saw, or draw a picture of it? Having a plan to get there won't do much for us if we don't know what there is.