Hester actually has two sins, but you don't discover the other one until later in the book. Her first sin, which is very obvious is committing adultery. her second sin however, is marrying Chillingworth. she says that marrying him was a sin because she did not actually love him, and she knew that she could not be faithful to him. She repents for this sin.
In Nathaniel Hawthorne's novel "The Scarlet Letter," Hester Prynne commits adultery, which is considered a sin in the Puritan society of the setting. She is publicly shamed and forced to wear a scarlet letter "A" as punishment for her sin. Hester's sin becomes a central theme of the novel as she grapples with its consequences and seeks redemption.
Adultery, I believe. If it's in relation to Hester Prynne in The Scarlet Letter. (Great read, by the way.)
Hester's sin - adultery
Hester Prynne had to wear a red letter "A" for "adultery" (it was her sin).
Pearl is the daughter of Hester and Dimmesdale and therefore resembles their sin of adultry. Hester dresses pearl in a scarlet colored dress to show this and make her look more like the letter "A" which also resembles their sin.
Hester worries that because Pearl was conceived in an act of sin - adultery - she is evil and only capable of sin. Hester sees all of her own flaws in Pearl, such as her stubbornness.
Hester becomes a symbol of sin and of women's frailty and simple passions.
Chillingworth blames Dimmesdale for Hester's sin of adultery. He believes that Dimmesdale is the father of Hester's child and seeks revenge on him for his part in the affair.
Hester first notices the A which shows that when people look at Hester, the first thing they see is the physical reminder of her sin.
The fact that Hester would constantly remind Pearl of the consequences of sin is what convinced the governor to let Hester keep Pearl. Hester supported herself and Pearl by sewing garments.
sin and disgrace
She is proof, and a constant reminder of Hester's sin (adultery)
The scaffold, the scarlet letter itself, and Pearl are all devices in "The Scarlet Letter" that symbolize sin and its consequences. The scaffold is where public shaming occurs, the scarlet letter is a physical reminder of Hester's sin, and Pearl embodies the product of Hester's sin.
Hester tells Pearl that she has no father and that she was born from sin. She refuses to reveal the identity of Pearl's father, choosing to protect his secret.