What evidence from the text supports the idea that lady macbeth believes her husband has decided not to kill the king because he is weak and cowardly?

The evidence from the text that supports the idea that Lady Macbeth believes her husband has decided not to kill the King because he is weak and cowardly is found in Act 1 (scene VII), lines 39-41 from the play:  "Art thou afeard to be the same in thine own act and valour As thou are in desire?".

These are the words that Lady Macbeth uses to instigate her husband to murder Duncan. She is angry when he tells her that killing him is not the right thing to do. Therefore, she questions Macbeth's manhood in order to convince him to go on with their plan since murdering Duncan will help him to become the new king. In that way, Lady Macbeth is the one that feeds her husband's ambition and instigates him to commit crimes.

the turtle carries new life, oat seeds, over to the other side of the highway and plants them there.