Duncan is a relatively flat character in Macbeth, largely because he gets murdered early on. In Act I, we are introduced to Duncan as the noble king of Scotland. Duncan begins by asking if the Thane of Cawdor has been executed yet, and reminiscing on the fact that it’s hard to know how to trust.
There's no art
To find the mind's construction in the face:
He was a gentleman on whom I built(15)
An absolute trust. (lines 13-16)
This foreshadows Duncan’s problems with the second Thane of Cawdor, Macbeth, a man who also betrays Duncan. Duncan trusts Macbeth, and actually feels bad that he was not promoted sooner.
O worthiest cousin!
Therefore Duncan is a little overly-trusting. He also comments on how he will further Macbeth and Banquo’s careers.
Duncan seems very caring also.
That hast no less deserved, nor must be known
No less to have done so; let me enfold thee(35)
And hold thee to my heart. (lines 33-36)
Clearly, Duncan is a nice guy who is full of affection and takes care of those whom he sees as friends and loyal servants, but he is a little too trusting.
duncan is a worthy king he has absolute love and respect for macbeth .he is very impressed with macbeths bravery and therefore gives him a promotion ad announces macbeth thane of cowdor