The youth and childhood of Chloris is stolen away when Zephyrus transforms her into a goddess. She then becomes a symbol of youth, laden with responsibilities. Similarly, Rico's transformation robs her of her full humanity. She becomes a kind of goddess, but instead of representing life, she brings death.
The way appearances deceive is a common theme in this episode. Moments after this picture, Rico talks about her brother's kindness seconds before the episode cuts to Jean just after he has cut off an assassin's ear in order to extract information. Moreover (and I didn't notice this until just now), earlier on, Rico stands with Fillipo in front of another famous Botticelli painting,
The Birth of Venus.
During this screenshot, two assassins are discussing why Rico likely isn't the "little girl" they've been warned to watch out for. Her hands are too clean, showing no signs of the intense training that would be required to be an assassin. They don't realize that she's more than human. Her angelic appearance hides her deadly nature.