When Goodman Brown returns to the village on the morning after the witches' Sabbath, he is very changed. He used to believe that his friends and loved ones were good people with good morals, but now he thinks that they are all false and two-faced. He no longer trusts the minister or the deacon, and when walking past the "good old minister" he "shrank from the venerable saint, as if to avoid an anathema." To him, the men he used to think of as so holy and good now seem wicked and cursed.
Likewise, when he sees his lovely wife, Faith, he "looked sternly and sadly into her face, and passed on without a greeting." He can no longer feel comfortable with her and shrinks away, just as he does from the minister. He no longer believes that these are godly people, and he cannot trust their appearance as such.
When he dies, Goodman Brown's neighbors "carved no hopeful verse upon his tombstone; for his dying hour was gloom." He had become a distrustful and miserable cynic by the time of his death.
I do not believe the narrator endorses Brown's unwillingness to trust. Brown had gone into the forest to meet the devil, just as all the others had. He is surprised to learn that his father and grandfather, the minister and deacon, and all his neighbors and friends are sinners, but he is a sinner too. Brown is no better or more trustworthy than any of the others, so what right does he have to judge others for curating similarly deceptive appearances of sinlessness? The narrator does not describe Brown sympathetically.