The quote reflects a deep introspection about the nature of love and how it can be overwhelming. The character is frightened by the enormity of his feelings for her, which implies that love can be both beautiful and intimidating. This complex emotion hints at the struggles one faces when confronted with the vastness of another person's heart and the expectations that come with such love.

In John Updike's "Rabbit, Run," this idea of love being vast resonates throughout the narrative, showcasing the character's inner turmoil and the challenges of romantic relationships. The fear of such expansive love suggests a need for both vulnerability and courage, as it can lead to profound connections but also to anxiety about commitment and loss.