In the Palace of the King by F. Marion Crawford

Dolores stood leaning against the back of the chair, neither hearing nor seeing her sister, conscious only that Don John was in danger and that she could not warn him to be on his guard. She had not believed herself when she had told her father that he would not dare to lift his hand against the King's half brother. She had said the words to give herself courage, and perhaps in a rush of certainty that the man she loved was a match for other men, hand to hand, and something more. It was different now. Little as she yet knew of human nature, she guessed without reasoning that a man who has been angry, who has wavered and given way to what he believes to be weakness, and whose anger has then burst out again, is much more dangerous than before, because his wrath is no longer roused against another only, but also against himself. More follies and crimes have been committed in that second tide of passion than under a first impulse.

Even if Mendoza had not fully meant what he had said the first time, he had meant it all, and more, when he had last spoken. Once more the vision of fear rose before Dolores' eyes, nobler now; because it was fear for another and not for herself, but therefore also harder to conquer.