There is a marked difference in the way that the document that the narrator finds about Hester Prynne remembers her and the impressions that we have of her character. In contrast to our automatic assocation of Hester with adultery, the document presents Hester as something of a saintly figure in her time. Consider the following presentation:
It had been her habit from an almost immemorial date to go about the country as a kind of voluntary nurse, and doing whatever miscellaneous good she might; taking upon herself, likwise, to give advice in all matters, as a person of such propensities inevitably must, she gained from many such people the reverence due to an angel, but, I should imagine, was looked upon by others as an intruder and a nuisance.
We are thus given a view of the kind of character that Hester Prynne became after the end of the main section of the novel, which interestingly comments on the situational irony of Hester Prynne's fate. She starts the story being scorned and rejected by society because of her sin of adultery, and in the end becomes regarded as a saint. This could be viewed as yet another example of the strange hypocrisy of Puritan society that Hawthorne writes so much about.