In Macbeth what does Lady mean by oh never shall sun that morrow see?

Lady Macbeth means that she hopes the sun will never rise on the next day because she cannot bear to think about what it will bring. She has just learned that her husband, Macbeth, has murdered King Duncan, and she is horrified by what he has done. She knows that they will both be punished for their crime, and she cannot bear the thought of facing the consequences.

Lady Macbeth's line "Oh never shall sun that morrow see" is a powerful expression of her despair and guilt. It shows that she is already starting to crack under the pressure of her guilt, and that she is close to the breaking point.

This line also foreshadows the events of the rest of the play. Lady Macbeth will eventually go mad and die, and Macbeth will be defeated and killed. The sun will not rise on a new day for either of them.