In Shakespeare's play Macbeth, Lady Macbeth is the main influence in Macbeth's life. In the beginning of the play, when the witches tell Macbeth of his promising future, Lady Macbeth is the first person he writes to. Upon hearing the witches' prophecy, Lady Macbeth wishes it to be true, hoping that she will become queen. That's when Lady Macbeth's evil side is showing (i.e. "Unsex me and fill from the toe-top full of direst cruelty!" (Act I, Scene V). Lady Macbeth wants to become strong enough to persuade her husband to kill Duncan.
Once Lady Macbeth brainwashes Macbeth into murdering the king, she begins to plan the murder. It seems like she planned the perfect murder. She wants to be crowned just as much as Macbeth, but she didn't have the courage to stab the king. Once the king arrives at Macbeth's castle, Lady Macbeth does what she told her husband to do.
This also shows Lady Macbeth's intelligence, for example, when Macbeth thinks further about killing the King, he decides that he has too many reasons not to do it. Macbeth believes that his ambition is the only reason to murder the king. Ambition is also Lady Macbeth's only reason for wanting to become queen. At the time when Macbeth tells Lady Macbeth that there is a change of plans, she uses a very smart tactic in trying to pursuade Macbeth. When Macbeth does as little as question her plan, she tells him "screw courage to the sticking place" (Act 1 Scene VIII). That method was successful into killing the king. This scene shows that Lady Macbeth is very powerful in this relationship. She is able to change Macbeth's mind even when he clearly said "We will proceed no further in this business" (Act 1 Scene VII).
After the killing is done, it doesnt seem to affect her very much. Her husband on the other hand is the total opposite. He forgot to place the daggers in the drunken guard's hands, and refused to go back. Lady Macbeth fearlessly grabs the daggers and returns them.