Complex sentence: Kara visits Lena to discern what she knows about her mother Lillian and Cadmus; after Kara leaves, Lena invites Lillian over to inform her that a reporter is raising suspicions about her.
Split into simpler sentences: Kara visits Lena Luthor to discern what she knows about her mother, Lillian Luthor and Cadmus. Lena alerts Lillian that a reporter is raising suspicions about her.