She was absolved from her promise.

She had been wrong to persist in keeping it, in his opinion; but at any rate she was honorably released from it now.

And she would marry him.
And that _second_ promise, which she had made to Dare, that she would still marry him if he were free to marry?
Charles moved impatiently in his chair.

From what exaggerated sense of duty she had made that promise he knew not; but he would save her from the effects of her own perverted judgment.

He knew what Ruth's word meant, since he had tried to make her break it.