Wanting someone and believing you don't deserve them: that tension drives these few short lines. The poem opens with a rush of feeling. Someone's heart "wrenches in anticipation," and the question that follows, how one person can make her "yearn so badly," sounds almost bewildered, as if the feeling is stronger than she knows how to handle.
Then the poem shifts. The speaker turns directly to the person she admires, praising their "kindness and gentleness," but quickly pulls back. She doesn't think they'd want "someone like me," and she ends by promising only "disappointment." The title, "I'm Not Perfect," gives away the heart of it. The pronouns also change, from "her" to "you" to "me," which makes it feel like the speaker is stepping out from behind a distance and then withdrawing again. The mood is tender but heavy, a mix of hope and quiet self-rejection. The poem leaves us with a feeling that she may never say any of this aloud.