In act 3, scene 2 of Shakespeare's tragedy Macbeth, there are three possible reasons why Macbeth chooses not to tell Lady Macbeth of his plans to kill Banquo.
The first reason is that Macbeth needs Lady Macbeth to assure Banquo that he is welcome and in no danger. Consider what he says to her in lines 30-35:
"So shall I, love, and so, I pray, be you.
Let your remembrance Apply to Banquo; present him eminence,
Both with eye and tongue: unsafe the while that we
Must lave our honors in these flattering streams,
And make our faces vizards to our hearts,
Disguising what they are."
Perhaps he feels that if she knew of his plans, Lady Macbeth would not be able to give a performance that would make Banquo feel that he had nothing to fear from either of them. He knows that they are in danger if anyone should begin to suspect their intentions. Consequently, in Macbeth's mind, it may be best to not involve her in his plans at this point.
When Macbeth hints that Banquo and Fleance
will soon be out...
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