Final answer:
St. John learns Jane's true name through indirect evidence rather than straightforward discovery, relying on observations and conversations.
Step-by-step explanation:
St. John discovers Jane's true name through a series of conversations and observations that give insight into her past and reveal her identity. Unlike other characters in the narrative, St. John does not exclusively rely on direct confessions or straightforward discovery methods to learn about Jane's true self. It is the indirect evidences, such as her reactions, interactions with other characters, and her moral and ethical choices throughout the story that allow St. John to uncover Jane's true name and character.