Even after many re-reads, I am always surprised about Jane Fairfax and Frank Churchill's engagement.
First, a secret engagement seems so out of character for Jane. She is elegant, reserved, always proper. And a secret engagement seems so improper. Since she's reserved, I guess she can hide a secret, but I never see any hints that she is not a perfect lady.
Second, I don't see the compatibility between Jane and Frank. Again, Jane is the proper lady and Frank seems to be anything but the proper gentleman. Mr. Knightley points out that Frank could have done his duty and visited his father upon his marriage. Jane seems so upright that I think this would be her view too. Frank's flirtations with Emma clearly hurt Jane but she forgives him, and we don't really see why.
What do others think? Are you as puzzled as I am about why Jane is attached to Frank?