I can't give page numbers because I doubt that we have the same edition of the book...
To me, the main insight that John Proctor has into his wife's character is that she is very honest. We can see this best when he tells the court that if she says she's pregnant there is no way she is lying. (Act III, Scene 2)
The main insight he has into himself can be seen towards the end of the play (Act IV, Scene 2) when he is trying to decide whether to lie to save himself. His insight is that he is not a "saint" like Rebecca Nurse, for example. He knows that he has flaws within his character.
John Proctor is Elizabeth Proctor's husband in the play The Crucible. John had an affair with Abigail. The girl had extreme jealousy over his wife. Elizabeth fires the girl and sends her away. Abigailin anger makes accusations against Elizabeth. Elizabeth is charged in a frenzied witch hunt. She could be free if she would tell on her husband. She is a honest woman who never lies. Yet, she lies for her husband by not telling of his affair. Elizabeth can be cold at times but she also has a good heart. Of preparing a rabbit for dinner she says;
"Elizabeth: Pray God. It hurt my heart to strip her, poor rabbit."(50)
Abigail has become saint like in the town because she has accused others falsely of witchcraft. She told John the truth but to reveal it he must reveal his own adultery. Elizabeth says to John:
"Elizabeth: "God forbid you keep that from the court, John."(53)
Elizabeth had pleaded with John to tell the truth on her behalf when the Reverend Hale visits to scrutinize her. Elizabeth is being interrogated about her involvement in witchery, and yet, she still does not lie and tells Hale that she does not believe in witches.
Elizabeth does not reveal the truth when she is lied on trial. Her husband pleads for her to tell it. He states:
"Proctor: "She only sought to save my name!"(113)
Hale after completing his investigations becomes aware that the people are innocent.
"Hale: "Its a lie! They are innocent!"