From the beginning of act 1 scene 5 till the murder of Duncan in act 2 scene 2, it is evident that Lady Macbeth manipulates and convinces Macbeth into murdering Duncan. This is basically the only part of the play where Lady Macbeth has control over Macbeth. After Duncan's murder, Macbeth is partly driven by evil powers.
Proof of Lady Macbeth understanding Macbeth's thoughts and feelings are visible in her thoughts "Thou wouldst be great, Art not without ambition, but without the illness should attend it." (1.5.19-21). From the very same speech and small implications from the letter, we can tell that Macbeth was ambitious enough to want to be the King, but would not think of murdering Duncan. Because Lady Macbeth knew this, she also knew that she would have to push Macbeth into performing the deed and she starts by telling him "Thy letters have transported me beyond this ignorant present and I feel now the future in the present" (1.5.57-59) the moment they meet. From Macbeth's reply "We will speak further" (1.5.69) he is obviously noncommittal, but was already thinking about it. The first step of manipulation has started.
Not much further in the play, we see that Macbeth decides not to murder Duncan but rather, carry on serving as his Thane. However, Lady Macbeth starts her persuasion again, but this time she questions his manhood, saying "When you durst do it, then you were a man: And to be