In "The Scarlet Letter", why does Hester repeatedly refuse to stop wearing the letter?

When the Reverend Mr.
Wilson questionsto get her to name her child's father, Hester repeatedly refuses. He tells her
that revealing this name and her own repentance "'may avail to take the scarlet
letter'" from her breast. She replies, "never, [...]. It is too deeply branded. Ye
cannot take it off. And would that I might endure his agony as well as mine!" Hester seems
to imply that she cannot stop wearing the letter because it isn't just a piece of cloth that she
pins to her clothes; it seems somehow more deeply impressed into her very body....