Macbeth is conflicted for several reasons. His desire to rule is in conflict with the fact that he must kill in order to do so, and he knows that this will damn him. He does not want to believe the prophecies of the witches, so he tries to rationalize their warnings in his mind. He is not really evil, but weak and insecure. In his heart, he knows he is not worthy to rule, but his wife wants him to commit murder in order to do so, and he wants to please his wife. He is too weak to stand up to her, and he allows her to manipulate him into doing her wishes. His guilt and inner conflict drive him to see Banquo's ghost at the feast and ultimately cause his downfall.