Why was Conrad so hostile toward her?

Once Christabel had thought he was the man with whom she'd spend her life—he had been far from indifferent to her on that brief holiday in England. Yet he had made their parting final.

But it seemed their destinies were entwined. She had traveled around the world to comfort the children her flighty selfish sister had left behind, only to face him again unexpectedly. Now, however, he had a different name, and this time he was her enemy.