In Washington Irving's "The Devil and Tom Walker," what convinces Tom that what the devil has told him in the swamp is true?
Washington Irving's "The Devil and Tom Walker" tells of Tom Walker's deal with the Devil. In order to obtain the wealth of Kidd the Pirate, Tom must become a usurer (one who lends money at a very high rate of interest). As with most deals with the Devil, the story does not end well for the one making the deal (Tom Walker).
When Tom first comes across the Devil, the Devil is cutting down a tree. The tree possesses a name: Crowninshield. The Devil tells Tom of the treasure and offers it to Tom. Unsure of the truth behind the treasure, Tom wants some time ot think upon it. Tom asks what proof he (Tom) has that the Devil's story is true. He (the Devil) places his thumb upon Tom's head, marking him with his signature.
When Tom reaches home, his wife tells him that Crowninshield has died suddenly. Tom remembers the tree with the name upon it. "He now felt convinced that all he had heard and seen was no illusion." He believes that the Devil possesses Kidd's treasure and can offer it to him in trade.