Are there any quotes in Macbeth that discuss trust?

Macbeth is all about trust and betrayal. So, here are two major examples of the abuse of trust in the play.

1. At the beginning of the play, king Duncan strips the traitorous Thane of Cawdor of his titles and has him killed because the thane conspired with the Norwegians against Duncan. Duncan was naturally disappointed because he trusted the thane:

There's no art
To find the mind's construction in the face:
He was a gentleman on whom I built
An absolute trust.

The King states that one's appearance can be rather deceiving and that although he trusted the thane, he was eventually tricked by him. What is ironic is that king Duncan will put his trust in another man who will betray him just like the thane of Cawdor did. And this man is, of course, Macbeth.

 2. When Macbeth confronts the dilemma of whether to murder king Duncan or not, he goes through the list of reasons why he should not kill the king. One of the most important reasons is because Duncan trusts him:

He's here in double trust;
First, as I am his kinsman and his subject,
Strong both against the deed; then, as his host,
Who should against his murderer shut the door,
Not bear the knife myself.

So, Macbeth states that Duncan trusts him for two reasons. First, they are relatives, so killing the king would not only be unacceptable, but sinful as well. Macbeth is also his most loyal subject, so he should support him, not murder him. Second, Duncan will be a guest at Macbeth's home, so, as his host, Macbeth should protect him and make sure that Duncan is safe. Nevertheless, we know that Macbeth will abuse this trust which Duncan has and take advantage of the fact that Duncan is at his home so that he could kill the king.