But mark you: he never takes a woman into dangerous confidences unless he thinks she loves him.

Do you follow?
Storri has told this to a woman in whose love he believes." "You reason well, at any rate," observed Richard.
"Yes, sir, I reason well," returned Inspector Val.

"I have reasoned like this a thousand times, and a thousand times I was right.

To go on: I agree with Storri; the woman does love him.

Why does she write this letter?
Because she wants to break Storri's grip on Mr.Harley.On Mr.
Harley's account?
No, she cares nothing for Mr.Harley.In a clash between the two her sympathies would be with Storri, whom she loves.