Complex sentence: Calypso is also furious that the Pirate Lords trapped her in her human form and her true motives are revealed: she plans to use her powers to betray the entire pirate fleet to Beckett in revenge.
Split into simpler sentences: Calypso is also furious that the Pirate Lords trapped her in her human form. Thus, her true motives are revealed: she plans to use her powers to betray the entire pirate fleet to Beckett in revenge.