text: It all depends on what A really thinks about C and whether B actually cares about C. But it gets more complicated if B and A do not quite agree on what C is. They may not even be aware of their disagreement. What then? B could be complicit in a lie while A is completely innocent, and of course A could be dishonest even if B is innocent. The calculus of sin can be quite messy. If that were not complicated enough, A could be seduced into believing C. B sends flowers, and A likes the way the light falls on Bs shiny hair. A and B might both be honest but just distracted, and so on.