Symbolically, Young Goodman Brown sees the ribbons abandoned, which represents his own disillusionment and the lose of his religious faith and his relationship with his wife Faith.
I think that the pink ribbons are a link between the conception of Faith as good and as evil. If Faith were purely good, her hair ribbons would have been white not pink. Indeed, pink was not an approved color in the Puritan society in which she lived. They wore somber clothes usually in dark colors. Thus I believe that the pink ribbons are a mixture of red for the evil of Satan, and the white of purity, thus combining the presentation of Faith as the virtuous wife waiting for her husband and the presentation of Faith as the evil harlot of Satan.
This is a difficult response for “Faith” is very ambiguous in the story, carrying more than two meanings. The ribbons are mentioned in conjunction with Faith when we meet her “thrust[ing] her own pretty head into the street, letting the wind play with the pink ribbons of her cap.” Her ribbons are mentioned two more times immediately: “Faith with the pink ribbons” blesses him as he leaves, and he looks back to see “Faith still peeping after him, with a melancholy air, in spite of her pink ribbons, causing him to think “Poor little Faith.” Putting these introductory passages together, faith can be bold, sufficient unto itself so that it can play “in the wind” and retain itself; faith can be good and trusting, which we see when Faith blesses Brown, and finally faith can be sad because it is not sufficiently strong to withstand adversity (“poor little Faith”). It is this final aspect of faith that the story leaves us with at its conclusion, for Brown’s faith was insufficient to trust in his wife and his neighbors, insufficient to allow him to retain a sense of humanity even if its sometimes marred by evil and guilt.