Riders of the Purple Sage by Zane Grey

As Lassiter had reported to Jane, Venters "went through" safely, and after a toilsome journey reached the peaceful shelter of Surprise Valley. When finally he lay wearily down under the silver spruces, resting from the strain of dragging packs and burros up the slope and through the entrance to Surprise Valley, he had leisure to think, and a great deal of the time went in regretting that he had not been frank with his loyal friend, Jane Withersteen.

But, he kept continually recalling, when he had stood once more face to face with her and had been shocked at the change in her and had heard the details of her adversity, he had not had the heart to tell her of the closer interest which had entered his life. He had not lied; yet he had kept silence.