Behind the Bronze Door by William Le Queux

Meanwhile Yootha Hagerston was secretly becoming more and more enamored of Captain Preston. It was the first time in her life she had ever really cared for any man; until now she had followed the fashion prevalent among many women of pretending to consider love and deep affection "all nonsense" and the hall-mark of a weak intelligence. She had come to know his movements and had discovered some of his haunts, with the result that she rarely missed an opportunity of meeting him "by chance."

And, though he would not have admitted it, even to himself, Preston had for some weeks past been singularly attracted by Yootha. He had liked her that day he had met her for the first time, at lunch at the Ritz and afterwards at Jessica's musical At Home, though the woman who had most interested him then had been Yootha's friend, Cora Hartsilver. But now it was different. There was something about the girl, apart from her looks, which appealed to him. What it was he could not have explained. It might have been her sympathetic nature, or her personality, or her temperament; in any case he felt strangely drawn towards her every time they met.