"Thank you for this, Peter. For dry eyes and silent weeping. You taught me how to hide anything I felt. More than ever, I need that now."Ch.5 Pg.33 Ender has been used to being taunted by Peter, so when Dap made him cry he knew how to put on a lying face.
"It's because if it were true,... Peter was not a monster, and so she could satisfy her Peter-like love of power without fear of becoming monstorous herself." Ch9 Pg.94 Valentine Knew what Peter was capable of, but was giving him a second chance and hoping she wouldn't turn into Peter.
" And then a worse fear, that he was a killer, only better at it than Peter ever was." Ch.8 Pg.85 As Ender looked at himself into the mirror he seen Peter's face. He was ashamed of seeing Peter inside of him he came to believe he really was a killer.
"But Ender,she did not want him to understand her. It would make her naked before him. She would be ashamed." Ch.13 Pg.167 Valentine didn't want Ender to understand her cruel thoughts she had when she was with Peter.
"The power to cause pain is the only power that matters, the power to kill and destroy,...you can't kill then you are always subject to those who can, and nothing and no one will ever save you." Ender beat up Bonzo so bad that it killed him, but Ender knew that Bonzo was coming after him so he had to defend himself quickly.
"Ender is unconcerned with ambition or power,and unlike Valentine, would be content to live a normal life." Valentine is obsessed with power and wouldn't be able to live a normal life because her life is already full of excitement and disasters.
"Valentine sees that he thinks she is trying to manipulate him and tells him that no one has a free life to live,so the least he can do is choose a path put forth by one who loves him." Valentine finally realized what Peter has been doing to them the whole time and has finally decided to move on.