"Lift the veil but once, and look me in the face."
Wow! This is Extraordinary!
"Tremble also at each other! Have men avoided me, and women shown no pity, and children screamed and fled, only for my black veil? What, but the mystery which it obscurely typifies, has made this piece of crape so awful"
I think that this was am effective ending to the story as perhaps Hawthorne decided for there to be no clear answer as to the veil, because maybe there was in fact no reason. Maybe Hawthorne was commenting on humanity's innate ability to assume the worst.
"Mr. Hooper’s face is dust; but awful is still the thought that it moldered beneath the Black Veil!"