Answer:
In "Young Goodman Brown," Hawthorne uses irony in order to develop both a theme and character. The plot of this short story centers around Young Goodman Brown, a Puritan who tries his best to remain pure. But, one night, he chooses to go off the path of purity in order to attend a witches' Sabbath. He promises himself that he will return to his former holiness the following day, but that comes to transpire. The irony in the story is when Brown wishes to return to his old Puritan beliefs, but is unable to. The theme is disillusionment develops as a result of this irony. Brown believes that he will be the man he once was after this night, but that is not the case. He sees many holy people at the Sabbath, resulting in the realization that not everything is not what it seems to be. Irony also plays a role in developing Goodman as a character. After experiencing the witches' Sabbath, Brown changes his character completely. It is ironic that the holiest people become devil worshippers, and this changes Brown's view of them when he returns to his village. He is no longer the man he once was, and though he anticipated that he will be, it never happened. Hawthorne uses irony to develop the theme of disillusionment and Young Goodman Brown as a character. In doing so, we can better understand what theme he wishes to convey to the reader, and what happens to Brown after the life-changing night.
Hopefully, this helps.