Final answer:
The protagonist's main motivation in The Rules of the Game is self-discovery and success in chess.
Step-by-step explanation:
The protagonist's main motivation in The Rules of the Game is self-discovery and success in chess. Waverly Jong desires to understand the rules that govern both the game and her life. This is evident in the text through her determination to master the game and navigate the complexities of her identity and environment. She studies the chessboard in her room and practices chess moves with her mother, demonstrating her motivation to achieve self-discovery and success.