Hi!
The following lines shed light on Machbeth's line of thought, which exhibits his reluctance to tell his wife of the murder before the deed has been done"
Be innocent of the knowledge, dearest chuck, till thou applaud the deed.
Here, the phrase. innocent of the knowledge, refers to ignorance of the deed, with innocent being suggestive of the wicked nature of the deed.
Dearest chuck is an endearment Macbeth regards his wife with, showing his affection of her.
Till thou applaud the deed roughly translates to 'when you find out about it', and here applaud is suggestive of the fact that Macbeth feels his wife would understand and be satisfied with the happening.
Hope this helps!