how does proctor feel when he sees rebecca nurse? what is it about rebecca's character that prompts him to feel this way?

The sight of Rebecca shames Proctor. He offers his confession, and Danforth asks him if he ever saw Rebecca Nurse in the devil’s company. Proctor states that he did not. Danforth reads the names of the condemned out loud and asks if he ever saw any of them with the devil. Proctor again replies in the negative. Danforth pressures him to name other guilty parties, but Proctor declares that he will speak only about his own sins.

Also John feels sinful and hypocritical in the sight of Rebecca Nurse who is considered honest and forthright. It is possible that, with a full confession, Proctor might have saved Rebecca but he refuses to.

Rebecca Nurse's presence and her influence and goodness have a distinct effect of Proctor. She is the epitome of goodness, that she stands ready for execution is the epitome of injustice. The vision of Rebecca is the thing that gives Proctor the strength to tear up his confession, by this act all of his untruths are forgiven and his soul redeemed.

It is Rebecca's refusal to bear witness against herself or others that upholds the goodness in Proctor. She comforts him on the way to the gallows and tells him, “Let you fear nothing! Another judgment waits us all!”