Ann tearfully telling Anne about her past sexual assault, genuinely believing she's Defiled Forever and Anne won't want her anymore. The episode ends with Ann sobbing into Anne's shoulder while Anne holds her and tries to comfort her.
Anne's utter heartbreak when Ann rejects her and calls their relationship sinful, particularly when she angrily reminds Ann that she has feelings, too, clearly holding back tears.
Anne's line to Ann in the first season finale: "Don't hurt me. I'm not as strong as you think."