In The Crimson Fairy Book (1908) there is a tale illustrated by H. J. Ford called The Boy Who Could Keep A Secret. When he was only a little boy, the king’s prettiest daughter tried to wheedle this boy’s secret out of him. Because he could keep a secret, he refused to tell, saying “I will beat anybody who asks me again.”
Fast forward until he is seventeen. The king’s prettiest daughter comes to him again:
“Tell me your secret and I will marry you,” she said to him; but the boy only gave her the beating he had promised her long ago, when she asked him the same question.
And that’s how you keep a secret: