Meshach's English Journal

I’d characterize Lady Macbeth as ambitious and ruthless. In either case, Shakespeare is clear in his portrait of Lady Macbeth, which we can see by examining her behaviour throughout the course of the play.
The first time we meet Lady Macbeth, she is reading a letter from her husband telling her of the witches’ promising predictions for his future. There is, apparently, love between them; Macbeth wants to share his fortuitous news with the woman he loves. She undoubtedly loves him; too however, she seems to know him well enough to be nervous for their future.
The first words she speaks after finishing the letter is about her husband “a man great in valour and unafraid of battle as a man lacking in ambition.” That’s not entirely true, as we find out later, but he clearly has less ambition than his wife. She’s afraid he won’t be willing to do what needs to be done (kill King Duncan) to achieve the goal of becoming King of Scotland. Once he arrives in person, she begins her campaign to spur her husband’s ambition into action.
On the night of the Duncan’s murder, Lady Macbeth has to convince her husband to do the deed. She is ruthless in her ambition, insulting his manhood and impugning his courage, saying she will do it if he is unwilling or unable. When it comes down to it, though, she can’t commit this cold-blooded murder. Soon after, though, Macbeth must sense some softening in his wife, for he fails to confide his next murderous plans to her. He plans and completes the murder of Banquo and the assassination of MacDuff’s family without telling her. His resolve grows as hers, apparently wanes.
As a result of ruthlessness in Lady Macbeth’s ambition she achieves the crown. She is racked with guilt and dies separated, at least emotionally, from the husband who she was a partner to at one time. Lady Macbeth is not a sympathetic character; however, she may not be an evil one, either.