The City in the Sea by H. De Vere Stacpoole

It was in his rooms that night, after supper, and comfortably seated before the fire, that Bobby's troubles began. Common-sense whispered into his ear:

"She will never know now that you cared for her, really. Bother Sam Hackett and her engagement to him. You should have told her, told her in the train or at the station. Instead of that you sat dumb as a fish, sulking. And who's Sam Hackett, anyhow, that she should care for him more than for you? He's a nice fellow enough; but look at him. He has neither good looks nor anything else. Is it too late to speak to her now? Yes, it's too late. These things can only be done on the spur of the moment. You had your chance in the train and it's gone. Imagine calling now at the office in cold blood and saying, 'I'm awfully sorry but I forgot to tell you something I ought to have told you before -- -- "