Which was plausible enough to be not so plainly spoken. The previous question was so obvious that it didn't even need to be said so bluntly (the meaning is that it is an obvious truth that a girl will be judged negatively when she asserts her freedom, so you don't need to say it because everyone knows it)

It is saying that by being seen in public with an older man, the girl may loss social standing. It’s implying that people might think that that she is in a relationship with him and/or no longer a virgin, having no virtue, etc. Running around in a convertible = driving to a variety of places Old rooster = an man past prime As for the second sentence’s meaning. It is possible that people might think it, but nobody would say it aloud. Plausible enough = likely or probable, easy to see being the truth Plainly spoken = bluntly said, speaking the truth to be understood