In his letter, Darcy tells Elizabeth that he had "often seen [Bingley] in love before". Now, can you picture Bingley being a "player", or doing something improper that might damage a young lady's reputation or feelings? I can't, but his partiality for whatever young lady he was in love with at the time must have been reasonably obvious. As I said in my previous post, I think that even in JA's time, there must have been some wiggle room before the serious business of choosing a life partner began!