What does Hester say she has learned from the A?

Hester says she has learned from the scarlet A that her punishment is "nothing compared to the tortures which I have brought upon myself." She also says that the A has "taught [her] a symbol...which burnt upon [her] in the shape of flame." In other words, the scarlet letter has taught Hester that her sin is a deep and serious one that will stay with her for the rest of her life.