Quote 10
"I was thinking," she answered grandly and politely, "that you did not know what you were doing." (11.37)
It takes some guts to stand up to Miss Minchin, who punishes Sara with horrible things like not giving her anything to eat for whole days. But Sara has too much courage to lie.
Quote 11
"I always was a thin child," she said bravely," and I always had big green eyes." (15.73)
Sara doesn't want to admit to just how starved and miserable she is. Why? Maybe because saying it would make it true—like telling the wrong kind of story about herself.
Quote 12
"I didn't want you to know," Sara said. "It would have made me feel like a street beggar. I know I look like a street beggar." (15.104)
For Ermengarde's sake, Sara keeps it together, even when her life is utterly depressing. She's like a leader putting on a brave face so her subjects don't panic.