I really noticed this snippet of conversation for the first time in many readings of NA, and I wanted to be sure I'm reading it the right way...

Isabella has just informed Catherine that John is supposedly in love with her.

"[Catherine]My dear friend, you must not be angry with me. I cannot suppose your brother cares so very much about me. And, you know, we shall still be sisters."

"Yes, yes" (with a blush), "there are more ways than one of our being sisters. But where am I wandering to? Well, my dear Catherine..."

Now, Isabella's blush is what I noticed. I see no reason for her to blush if she's talking about James, or about Catherine and John Thorpe. It occured to me that she could be referring to a marriage between herself and Captain Tilney, with her and Catherine becoming sisters if Catherine was to marry Henry. The next line, "But where am I wandering to" seems to confirm this. What do others think? It seems amazing to me that Isabella is so very scheming - she's already planning marriage to Captain Tilney, even though she and James have only been engaged a few days!