Because of the historical accuracy of this novel as well as its place among great classic literature, the reader knows even before the end of the book that this story will have a tragic ending. And Hawthorne's warning is absolutely true. Despite the fact that readers today celebrate Hester Prynne and her accomplishments, when she died, she died in shame.
The original quote reads "human frailty," and the fact is, Hester Prynne is frail. Despite the fact that she continues to live in the colony and daily bears her shame both physically and mentally, and then the fact that she is able to raise her daughter in the midst of this, she herself would probably admit defeat. She never lets go of the feelings of guilt. She never gets to experience a pure and open form of love with Dimmesdale. She never really even gets to experience complete transparency as a mother. She is human. And she is frail. And because of these things, her story is a tragedy.
It is easy to forget this, or overlook it, I think, because for centuries, audiences have read about Hester Prynne and elevated her upon that scaffold as a revolutionary woman, a victim of a time and place in history, when clearly she was meant for more and deserved better. But in context, Hester never experienced victory. She never truly felt absolution. And while we can celebrate her now, centuries later, Hawthorne is right to remind us that we can only do this because of Hester's human frailty and sorrowful story.