My reference to trust had absolutely nothing to do with being talked about the next morning or various levels of decorum, for the record. Even in a one-night stand context, I don't see myself getting close enough to a man who was so obviously lacking in respect that calling me a the next day would even be a concern.
The context to which I was referring, however, had more to do with being honest about why you're ing. I would need there to be enough trust for me to openly tell the guy that it's just sex and nothing more, and I would need there to be enough trust for him to openly tell me the same thing. For instance, guys who tell women that they're more important to him than they may actually be just to get her into bed have no room to complain when she's still expecting some sort of closeness or intimacy a few days later. And vice versa, frankly, because I know plenty of women who have used the same games to get men into bed.