In Act 1, Scene 5, Lady Macbeth reads Macbeth's letter about the prophecies of the three witches. Look carefully at the two passages spoken by Lady Macbeth after reading the letter. She expresses her true feelings about the prophecies in these passages.
In the first passage, she shows that she is immediately confident that these prophecies should come true. However, she has doubts about her husband's ability to help the promise of becoming king come true. She says,
"Yet do I fear thy nature;
It is too full o' the milk of human kindness
To catch the nearest way..."
Since Lady Macbeth fears that her husband will not be able to achieve greatness on his own, she feels that she must prepare herself to assist him. In a well-known soliloquy, Lady Macbeth 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!"
When she says "unsex me", we can see that she feels that she must become less womanly and more manly in order to be ruthlessly ambitious. This brings up the issue of gender roles. Women seem to be associated with caring and nurturing while men are associated with toughness and strength. Lady Macbeth's willing abandonment of all that is soft and comforting in a woman has made her a symbol of feminine deception.
This line is a paradox. it means that everything is reversed in the world of evil. What is percieved as good will be bad and what is percieved as bad will be good. No essay explanation needed. :p
She is getting more excited about killing the king after he arrives. She does not wish to be a sympathetic "woman" and wants a hand in the murder. She orders her husband how to think and feel about the murder.