How did Macbeth realize betrayal had a strong influence on him in Shakespeare's Macbeth?
Before Macbeth murders King Duncan, his thoughts of betrayal to the King cause hallucinations. Macbeth sees a floating dagger that is leading toward where King Duncan sleeps. Macbeth is already feeling the effects of betrayal, even before he commits the murder.
Next, Macbeth is influenced by the murder of King Duncan in that he cannot even say "Amen" as the guards are praying. He shares with Lady Macbeth that he could not even pray:
One cried, "God bless us!" and the other, "Amen."
As if they had seen me with these hangman's hands.
Listening to their fear, I couldn’t say "Amen,"
When they said, "God bless us.
As he commits the murder of King Duncan, Macbeth keeps hearing that he has murdered sleep. He realizes he shall sleep no more, not a true sleep:
I heard a voice cry, "Sleep no more!
Macbeth murders sleep," the innocent sleep,
Sleep that knits up the raveled sleeve of care,
Macbeth is being influenced by his act of betrayal. He is having hallucinations and he is hearing voices. He is deeply affected by his act of betrayal in murdering King Duncan. He shares with Lady Macbeth that he forgot to plant the daggers on the guards, but he is afraid to go back and look on the gruesome murderous scene. Fear had gripped his being:
I'm not going back.
I am afraid to think about what I have done.
I don’t dare look on it again.
Furthermore, Macbeth sees Banquo's ghost after he has Banquo murdered. Macbeth is greatly influenced by his acts of betrayal. He betrays King Duncan. Then he betrays his close friend Banquo. His visions are terrifying hallucinations which seem real to Macbeth:
Blood has been shed before now, in the old days,
Before laws cleaned up the commonwealth.
Yes, and since then too, murders have been performed
Too terrible to hear. The time has been,
That, when the brains were out, the man would die,
And that was the end of it. But now they rise again,
With twenty mortal murders on their crowns,
And push us from our stools. This ghost is more strange
Than such a murder is.
Clearly, Macbeth is terribly influenced by his acts of betrayal. He has just begun his journey of sleep deprivation and ghostly hallucinations. He will never rest again. He will be tormented in his mind until his death.