Giovanni Guasconti is obviously very much struck by the beauty and grace of Beatrice Rappaccini when he sees her in her father's garden. He finds her to be enchanting in her loveliness, her voice like a "gush of music," and her manner innocent and childlike. Seeing that she obviously cares a great deal for plants and flowers, he buys her a bouquet in the market and tosses them down to her from his window when he next sees her alone in the garden. Beatrice picks them up from the ground and, apparently embarrassed at having dropped her "maidenly reserve" with him, she quickly makes her way out, toward her own home.

But, few as the moments were, it seemed to Giovanni when she was on the point of vanishing beneath the sculptured portal, that his beautiful bouquet was already beginning to wither in her grasp. It was an idle thought; there could be no possibility of distinguishing a faded flower from a fresh one, at so great a distance.

In other words, Giovanni thinks that he sees the flowers begin to die within moments of Beatrice picking them up. Perhaps, we might reason, this is why she leaves so quickly.

After this interaction, he avoids the window that overlooks the garden and realizes that he has "put himself ... within the influence of an unintelligible power" by beginning a communication with Rappaccini's daughter. He thinks that he probably ought to leave Padua, but "he had a quick fancy," and Beatrice has infected his system with something akin to both "love and horror"; so "hope and dread" war within his heart, keeping him there.