Ezekiel Dean's speaker is smitten with someone and admits it in a gently funny way. At first, he claims the person's flaws don't exist at all, since he can't see them when he looks at or listens to them. Then he corrects himself: whatever flaws do exist must be "the best" and "most perfect" of all. It's the kind of overstatement people make when they're infatuated.
The second half slows down and becomes more sincere. As the speaker gets to know this person, he starts to notice their "beautiful mistakes" and the little pauses in their speech, and he treats them as something to cherish rather than something to fix. He listens patiently, hangs on every word, and wants to hear their problems so he can show concern.
The mood is warm, tender, and a little shy. The poem moves from playful adoration to quiet, attentive care, suggesting that real affection means paying attention to someone as they are.