Fun fact: First thing Snape ever asks Harry was, "Potter! What would I get if I added powdered root of asphodel to an infusion of wormwood?" In Victorian Flower language, asphodel is a lily that means my regrets follow you to the grave. Wormwood means absence or bitter sorrow and regret. Add it together and you get, "I bitterly regret Lily's death." So Snape confessed his love for Lily to Harry in Victorian Flower language.