The other reason why John wished his presence at Rutland unknown was that if he were supposed to be in London, no one would suspect him of knowing Dorothy Vernon.
You must remember there had been no overt love-making between John and Dorothy up to that time.

The scene at the gate approached perilously near it, but the line between concealment and confession had not been crossed.
Mind you, I say there had been no love-making _between_ them.

While Dorothy had gone as far in that direction as a maiden should dare go--and to tell the exact truth, a great deal farther--John had remained almost silent for reasons already given you.

He also felt a fear of the girl, and failed to see in her conduct those signs of intense love which would have been plainly discernible had not his perceptions been blinded by the fury of his own infatuation.

He had placed a curb on his passion and did not really know its strength and power until he learned that another man was soon to possess the girl he loved.