The quote reflects the emotional disparity between two characters, highlighting a deep contrast in their experiences of pleasure and joy. The speaker understands pleasure intimately but recognizes that it can become dull over time. In contrast, joy is an entirely different emotion, one that feels out of reach and foreign, suggesting a lack of connection or understanding in that area.
Caro, on the other hand, embodies a complete and genuine experience of love, making her happiness appear almost extraordinary or exotic to the speaker. This distinction underscores themes of emotional isolation and the varying depths of human connection, illustrating how one character's fulfillment in love starkly contrasts with another's struggle to grasp similar feelings.