Why does Pearl pull away form Dimmesdale?

Hester and Pearl are at the scaffold because they have been at Governor Winthrop's deathbed taking measurements for a robe. Dimmesdale invites them to join him on the stand, which they do. All three hold hands and Pearl asks him, "Wilt thou stand here with Mother and me, tomorrow noontide?" Dimmesdale answers, "I shall, indeed, stand with thy mother and thee one day, but not tomorrow." Pearl persists in her question, and Dimmesdale answers that, "the daylight of this world shall not see our meeting." This is when Pearl pulls away. She doesn't quite trust this guy yet.