Mi beloved companion took this too as the effect of spring; how can they know what this is, this new song of the lover?

This beautiful couplet speaks to the unique, often misunderstood world of the lover's heart. The poet suggests that the joys and emotions experienced in love are so profound that mere companions cannot grasp them. They see the surface beauty—the 'spring'—but they don't understand the intricate, new magic of the passion itself. It’s a plea to those who truly understand the depth of romantic feeling.