Who reassures Ralph by telling him that "[he'll] get back to where [he] came from" and why might this be significant?
Piggy: he's the most logical thinker on the island, so his words make Ralph believe that rescue is not just a dream, but a probable outcome.
Piggy: as someone who refuses to believe in the beast, Piggy may be the boy with the strongest ties to civilization, and the one who best understands Ralph's longing for home.
Jack: in spite of the tension that has grown between the two of them, Jack still understands that Ralph wants to help the group get rescued.
Simon: his words don't quite have the desired effect as Simon's pattern of odd behavior (fainting, wandering into the woods alone at night, saying that the beast is one of them) makes Ralph think he's crazy.
Simon: his words help soothe Ralph's anxiety not because he can offer a logical reason that rescue will happen, but because he seems to understand on some emotional level what Ralph is going through.