What drives Goodman Brown and what is he seeking in "Young Goodman Brown"? Does he find it?

It's reasonable to think that Goodman Brown is seeking to test the strength of his Puritan faith. He seems to think it is unshakable, and so he actively seeks to meet with the devil to see if he can withstand any temptations he might have to offer. He seeks confirmation that he is on the right path with regard to both his earthly life and his afterlife.

Goodman Brown's faith remains intact, and one might argue that since the Puritan faith was rather dark in its outlook on humanity, what happens to Brown in the woods confirms his religious inclinations. Puritans tended to search themselves for signs of their own sinfulness, and since Brown spends an evening consorting with the devil, he acknowledges and embraces his own imperfection. Moreover, Puritans tended to be judgmental of others, and Brown becomes, in the words of the narrator, a "stern, a sad, a darkly meditative, a distrustful, if not a desperate man," after the sojourn in the woods.

What is Goodman Brown's motive in "Young Goodman Brown"?

While we never learn exactly what compels Goodman Brown to go into the forest, we do know, at least, that his motives are not upright or pure. His new wife, Faith, all but begs him not to go that night, but he insists that he must. Then, as he walks away from his home, he calls himself a "wretch" to leave her to go on "such an errand." If he were motivated by something good, he would hardly refer to himself as miserable or to his trip in such a derogatory way. He fears, momentarily, that a dream may have "warned her what work is to be done to-night," but he assures himself that this cannot be the case. It would "kill her to think it," he believes; if she knew his purposes, then, it would kill her. Now, if he were merely planning a trip to the forest for some innocuous purpose, he would surely not have to go between sunset and sunrise, nor would it kill his wife to know what he is up to.

The most compelling evidence that Goodman Brown is motivated by sinfulness is his plan for the future. He thinks that his wife is a "blessed angel on earth; and after this one night, [he'll] cling to her skirts and follow her to Heaven." In other words, he knows very well that his resolve to be good and live righteously begins tomorrow—not now—and so it seems that he wants just one more night of sinning to sow his wild oats.