Shakespeare makes Lady Macbeth such an interesting and dramatic character that she overshadows her husband in the first part of the play. What makes her such an interesting and dramatic character is mainly her strong motivation. She knows what she wants and insists on getting it. At the same time, however, she is able to hide her true character and her true motivation behind a mask of modest femininity. She tells her husband, "Look like the innocent flower, but be the serpent under it." King Duncan loves her. He calls her, "Most kind hostess," among other things. Her first greeting to Duncan in Act I shows her duplicity:
All our service,
In every point twice done and then done double,
Were poor and single business to contend
Against those honors deep and broad wherewith
Your Majesty loads our house.
This comes in scene 6, right after she has told her husband they must kill Duncan that very night.
After the murder has been committed and the body discovered, it is Lady Macbeth who keeps encouraging her husband to act friendly and innocent, while he seems to be having a nervous breakdown. She is a pillar of strength. She had nerves of steel. She says that she would have killed Duncan herself if she hadn't thought he resembled her father as he slept (2.2.16-17) Macbeth would never have gone through with the murder if it hadn't been for the encouragement of his courageous and strong-willed wife. When he refuses to go back to Duncan's chamber with the daggers to smear the faces of the drugged grooms with blood, she does it herself.
Macbeth loves her and is emotionally dependent on her, but he is afraid of her.