In The Scarlet Letter, what is the effect of the committed sin on the main characters?
The most interesting aspect about the analysis of Hester's sin, and its influence on the main characters is that, had Hester not become pregnant, she could have continued to live her life freely and, similarly, Dimmesdale would have probably never experience the guilt and self-deprecation that he feels. The "problem" begins with Pearl, since her conception is what opened up the secret to everybody.
This being said, Pearl's birth is what has really affected the characters because she is, literally, living proof of Hester's indiscretion. As a result, the effects on each of the main characters is negative, detrimental, and destructive...all except for Hester.
Hester learns throughout the story about how to live with her choice. She faces society, continues to hold her head high, and even finds strength in her scarlet letter. She seems to basque in her notoriety, to a point, for she openly flaunts Pearl as if in defiance of the hypocritical society that judges her so harshly. However, the sacrifices with Pearl, and her loyalty to Dimmesdale's name, do not preclude her redemption, neither physical nor spiritual. Even in the end, after Dimmesdale confesses, she still is jilted by him.
And was this the man? She hardly knew him now! He, moving proudly past...he, so unattainable in his worldly position...Her spirit sank with the idea that all must have been a delusion, and that...there could be no real bond betwixt the clergyman and herself.
Chillingworth's main drive in entering the settlement is to terrorize Hester, and to find out who is the man with whom she cheated. In Chillingworth, the effect of Hester's sin is crippling, since it makes him change his name and life forever in order to go after another man's fate. As a result, Chillingworth's evilness comes through his physical features, making him look strange in front of everybody. In other words, he is literally consumed by his rage and hunger for revenge.
Roger Chillingworth’s aspect had undergone a remarkable change while he had dwelt in town... At first, his expression had been calm, meditative, scholar-like. Now, there was something ugly and evil in his face, which they had not previously noticed, and which grew still the more obvious to sight...
It is Dimmesdale, however, who is mostly affected by Hester's sin, for his suffering is both psychological and spiritual. A man who is held in the highest esteem, Arthur Dimmesdale would have had to step down the pedestal of admiration that the settlement had built in his name. Admitting his sin to the settlement would be the proper and liberating thing to do, but he is unable to do so for many different reasons; namely, because the consequences would bring the settlement apart. Therefore, Dimmesdale implodes becoming a shadow of himself. His self-punishment only achieves more physical weakness and his appearance, like Chillingworth's, reflects that the main effect of Hester's sin on him is that it demonstrated that he was, perhaps, what he feared to discover himself to be: a fake saint of clay made up by the hysterics and silly fanaticism of an ignorant crowd of followers.
Therefore, none of the characters is redeemed nor changed for the better as a result of Hester's sin. In fact, they all end up isolated and left behind. Pearl as the only one with a bright future. This is because Pearl, although is a child of sin, is still innocent of the choices of others. This innocence is her redemption from the sins of others.