From our perspective, why does she faint?

The characters in the play had thought that she fainted because she couldn't handle that someone had died under her roof. When Macduff had told her Duncan was murdered she replied with "Woe, alas! What, in our house" (Shakespeare Act 2, Scene 3). She said this to make it sound like she was surprised it had ever happened, and that it should have never happened in her household. The audience knows that she had pretended to faint to act like it was a total surprise and was so sad, so no one would think she had anything to do with it.

“I laid their daggers ready;

He could not miss 'em. Had he not resembled

My father as he slept, I had done it.”

Lady Macbeth said this and this quote reveals that she was prepared and ready to kill someone, unlike most people who wouldn't even think of doing it

“One cried 'God bless us!' and 'Amen' the other; As they had seen me with these hangman's hands. Listening their fear, I could not say 'Amen,' When they did say 'God bless us!'”

This is spoken by Macbeth. He is saying that he feels unholy because of his recent actions. When he says "Listening their fear, I could not say 'Amen,' When they did say 'God Bless us!'" (Shakespeare, Act 2, Scene 2). He feels like he can't say godly words since he has done an ungodly action. 

The dagger represents guilt because Macbeth is talking about how he couldn’t put back the daggers he killed King Duncan with because he couldn’t believe he actually killed someone of high importance. The daggers were the objects that were committing the crime so they represent the guilt Macbeth felt.  “Listening their fear, I could not say 'Amen,'”(Shakespeare 28).

“O gentle lady,

    'Tis not for you to hear what I can speak:

    The repetition, in a woman's ear,

    Would murder as it fell.”

The speaker of this quote is Macduff. This is an example of dramatic irony because Lady Macbeth was the one who planned the murder. She is supposed to be a lady and not murder or plan to murder people. Macduff is scared that Lady Macbeth would faint if she knew that there was a murder but he didn’t know that she was the one who actually planned the whole scheme.   

“Will all great Neptune's ocean wash this blood

Clean from my hand? No, this my hand will rather

The multitudinous seas incarnadine,

Making the green one red.”

“Is this a dagger which I see before me,

    The handle toward my hand? Come, let me clutch thee. I have thee not, and yet I see thee still. Art thou not, fatal vision, sensible To feeling as to sight? or art thou but A dagger of the mind, a false creation, Proceeding from the heat-oppressed brain?” 

The speaker is Macbeth and the quote is about Macbeth seeing a dagger floating above Duncan's bedroom door it shows how Macbeth was second guessing himself but after seeing the dagger as a "sign" he followed through with the deed.

In act two after Mcduff divovered that that king has been murdered and when he is informing people of this, because lady's are considered innocent, he tells her, “''Tis not for you to hear what I can speak: 

The Repetition, in woman's ear, 

Would murder as it fell.” However Mcduff doesn't know that Lady Mcbeth knows about and participated in the murder. It makes the readers feel like the Mcbeths will get away with the murder and the predictions look more likely, it also has a note of dark humor as lady Mcbeth is being spared from hearing about the murder she helped commit because she is considered “innocent”.

Discuss the symbol of guilt?

One symbol of guilt in Macbeth is blood. When Macbeth and lady Macbeth kill the people they have blood on their hands and lady Macbeth starts to see it on her hands. 

Will all great Neptune's ocean wash this blood clean from my hand? No, this my hand will rather the multitudinous seas incarnadine, making the green one red" (Act 2, Scene 2).