The song 'No More Rhyme' by Debbie Gibson explores the theme of uncertainty and fear in relationships. The lyrics depict the struggle of maintaining a connection when faced with doubts and the fear of losing the rhythm and harmony that once existed. The metaphor of 'no more rhyme' symbolizes the loss of coherence and stability in the relationship, questioning what happens when the familiarity and comfort fade away, leaving behind uncertainty and the need to confront challenges together.