I think we have to be careful of taking The Rules of Regency life *too* seriously. Yes, marriage and reputation were a serious business for Regency women, but I do think there was *some* wiggle room, especially for an attractive young woman of only 20. Even in JA's day, not every pleasant romance was automatically expected to end in a marriage proposal! IMO, Col. Fitzwilliam handles the situation beautifully. He is attracted to Elizabeth and has enjoyed her company, but now that he is leaving, he lets her know in a clear but unembarrassing way that there will be no more to it. If he had left with Elizabeth still wondering what his intentions were, *that* would be poor manners (and morals), IMO.