Complex sentence: Lucilla is then "betrayed", and taken before the Great Honored Matre Dama, who tries to persuade her to join the Honored Matres, preserving her life in exchange for Bene Gesserit secrets.
Split into simpler sentences: Lucilla is then "betrayed", and taken before the Great Honored Matre Dama. The Matre tries to persuade her to join the Honored Matres, preserving her life in exchange for Bene Gesserit secrets.