The most obvious way we see her change is her mindset and attitude toward guilt. In the beginning she is ruthless and will do anything to make sure her husband becomes king. We see this right away when we first meet her in Act 1, scene 5. She receives the letter from Macbeth and immediately sees the opportunity and starts to make plans. She questions Macbeth's strength and if he's too kind to go through with the plan. She says
"Come, you spirits
That tend on mortal thoughts, unsex me here,
And fill me from the crown to the toe top-full
Of direst cruelty! make thick my blood;
Stop up the access and passage to remorse,
That no compunctious visitings of nature
Shake my fell purpose, nor keep peace between
The effect and it! "
She continues with this heartless attitude and mocks her husband when he seems weak. While he feels guilty about the blood on his hands, she says "a little water clears us of this deed."
But later in Act Five, the guilt and remorse come to haunt her. She is sleep walking and muttering about the horrible act of killing Duncan. She literally goes crazy with guilt. Her comments about the blood come back in this scene where she is making a washing motion with her hands and saying "Out damn spot."
Lady Macbeth goes from being violent and kind of insane to being timid and really insane.
Early in the story, she wants Macbeth to be king no matter what he has to do to get it. As a result, she is able to convince him pretty strongly to kill King Duncan. When she thinks that will be enough is not clear. He also has to frame the king's sons and kill Banquo.
Lady Macbeth soon begins to regret what she has done, and what her husband has become. Before long, she starts to doubt herself. When Macbeth sees Banquo's ghost, she is worried--especially since there are witnesses.
Finally, she seems to break. She begins sleepwalking, hallucinating that the metaphorical blood on her hands is really there, and she can never wash it off.
The above commentators have tried to point out how differently Lady Macbeth has been projected throughout the play. However, it is crucial to note how her character changes throughout the play. Lady Macbeth has been projected in three different ways. She is a provoker at first, a saviour in the middle and a psychiatric patient at the end of the play. Lady Macbeth changes from a provoker to a saviour because she succeeds in transforming Macbeth from a ‘fair’ to a ‘foul’ creature. Once the provocation is successful Lady Macbeth tries to save Macbeth from problematic situations (e.g. in Act II, Sc. iii she faints). When Macbeth does not let Lady Macbeth know about his intention to kill Banquo, the audience becomes aware of the fact that Macbeth is now beyond her control. Lady Macbeth therefore is projected as a character who is wounded in her psyche by the evil powers that she has invoked to provoke Macbeth. In the final section of the play that wound transforms her into a psychological patient who again and again tries to clear the evidence of her deed from her own hand.
Lady Macbeth is portrayed as being monstrously evil in the first three acts of the play. When her character is first introduced, her strength and ambition are evident as she assures her husband that the witches' prophesy will indeed come true, even as she questions whether Macbeth has the fortitude to make sure that it does. She expresses her concern, thinking, "I fear thy nature; it is too fullo' the milk of human kindness to catch the nearest way" (I,v,16-18). Because of this, she makes herself the driving force behind her husband's endeavors to win the crown. She laments her womanhood, and, in a chilling compact with evil, prays to be "unsexed" because she thinks that her femininity makes her weak (I,v,41-50).
Lady Macbeth is much different character in the final two acts of the play. Tormented by guilt and the havoc which she has put into motion, her mind becomes "infected" (V,i,72). She imagines that she has blood on her hands which cannot be removed (V,i,35), and, consumed by her own ruthlessness, she decends into madness. Ironically, Lady Macbeth is humanized in her weakness, showing a touching if deranged concern for her husband even in the midst of her own depravity. She repeatedly reassures the absent Macbeth that he has nothing to fear because "Banquo's buried, he cannot come out on's grave" (V,i, 62-65). Lady Macbeth's decline ends in suicide.
Lady Macbeth starts off innocent until reading the letter from Macbeth, telling her about the witches' prophecies. She quickly changes and becomes cold-blooded and starts plotting against Duncan. She persuades Macbeth and pushes him into doing the deed. After the first murder, she starts feeling guilt but Macbeth's desire of power grows stronger. Lady Macbeth feels anxiety and guilt, then beginning to hallucinate. Her health becomes really bad and she kind of turns into a mad-woman. She ends her own life by jumping off the ramparts of her castle.
well at first she was blood thirsty and all for the murder of King Duncan,and she was constantly telling Macbeth dont think about the murder,whatever is done cannot be undone,she also says that if we do think about the murder of Duncan it will drive us mad.So it appears in advance she sort of knows that thinking about the murder of Duncan would drive her crazy,which is foreshadowing what actually happens later in the play.She also questions Macbeth's manhood and tells him she'd rather kill her own child than to break a promise.At the end she pays her price,her guilt evetually just builds up so much that she committs suicide.So yea just the knowledge of Banquo's death and Lady Macduffs' Family's death drives her insane.
Lady Macbeth is one feisty character. She does not wait for things to fall into her lap, she takes matters into her own hands. She makes things happen. She knows what she wants and how to get it- at all cost. She is a very exciting character, very ambitious, ruthless and her morality leaves a lot to be desired. She did not think twice about plotting to murder King Duncan. She persuaded her husband to murder King Duncan by continuously questioning his manhood and capabilities, “Art thou afeard. To be the same in thine own act and valour. As thou art in desire? (Macbeth, I, vii)”.
Her husband hesitated numerous times and almost did not push through with the plan but Lady Macbeth steely determination abets him to continue with the plan to commit crime. Sparknotes believes that Shakespeare uses the women to push Macbeth “undaunted mettle should compose / Nothing but males” (I.vii.73–74).
After the murder occurred, Lady Macbeth changes for the worst. Ambition blinded her before the murder but guilt defeated her after. She may be too ambitious but still her conscience bothers her. “A little water clears us of this deed: How easy is it, then!
(Macbeth, II, ii). Her life and her sanity slowly fall apart. Lady Macbeth’s guilt leads to her untimely demise as she commits suicide. A very tragic end triggered by one tragic night.