The info she gave them in chapters 1,2, and 4 were vital information no matter how you interpret it. Chapter 3 is still vital info but some of you just don't understand it. But the fact that the Demon Lord could not fully utilize any of it is on the Demon Lord and his army. Additionally, I don't think the Princess lived a bad life, she was just treated as any man would be during a period of increasing tension and subsequent war in an era of kingdoms.