Two more similes complete the list in the third quatrain. Music is more pleasing than the voice of his lady, the speaker admits. And the speaker also adds that his lady walks solidly on the ground. She does not float above the air like a goddess.
In the final lines, the couplet, however, the speaker praises her beauty. He claims that his lady is as beautiful and special or "rare" as any woman may be or as any object in nature may be. He does not need to falsely compare the lady to images in nature because such comparisons would be untrue. They would be lies. For the speaker, the beauty of his lady matches (or is equal to) the beauty of nature even though her beauty is of a much different kind. In the footnote, our editors suggest that the word "rare" can also mean extraordinary. The beauty of the lady is extraordinary. It is wonderful. For the speaker, the lady's beauty is enough. It does not need to be compared to anything else.