Complex sentence: Though the crowd is delighted, the acrobat's cruel sister, despising the prospect of returning the spectators' money, reveals that she has a contract binding the two to perform the stunt, swearing to put them both in prison if they refuse.
Split into simpler sentences: Though the crowd is delighted, the acrobat's cruel sister rebels as she hates the prospect of returning the spectators' money. She reveals that she has a contract binding the two to perform the stunt, and swears to put them both in prison if they refuse.