The speaker is pleading with someone they love, and they hold nothing back. The opening images are physical and humble: kisses on the knuckles, knees at the other person's feet. Kneeling suggests devotion, but also a kind of desperation, as if the speaker has already lowered themselves as far as they can. The line "I love you floating between our lips" is the tenderest moment. Love becomes something almost visible, hanging in the small space between two mouths, unsaid and said at once.
Then the tone shifts into a direct appeal. "I'll treat you better than she could" suggests the person being addressed is with, or has been hurt by, someone else. The speaker doesn't argue for long. They simply ask for an open heart and a chance. The mood is intimate, vulnerable and hopeful, with an edge of longing, since we never find out whether the answer is yes.