Here, a speaker is saying farewell to someone they clearly care about, and they don't want to let go. The poem opens with a tear and a hug that lasts "too long," which tells us right away that this goodbye is hard. Then comes a whispered compliment, "You're cute / So beautiful," the kind of thing people say when they're afraid they won't get another chance.
The lines are short and plain, and that suits the moment. Nobody gives a polished speech while crying in someone's arms. The speaker's words come out in fragments, almost like gasps. "Oh dear" feels like a small sigh of helplessness, a mix of tenderness and sadness.
The final line, "My dear goodbye," is a nice twist. "Dear" usually describes a person, but here it describes the goodbye itself, as if the parting is something precious the speaker is reluctant to finish. The mood is gentle, affectionate, and bittersweet. The poem doesn't say why the two are parting, so we are left with just the feeling.