billd91
Not your screen monkey (he/him)
Why have the player roll if the result isn’t going to affect the outcome? Seems like this would undermine the players’ confidence in the consistency of your world’s responses to their actions.
Because there may still be other information they can glean from the situation other than just whether or not the speaker seems sincere. Plus, there may be some people who never seem sincere even when they are. And from the player perspective, that using their skills to analyze someone's mood, truthfulness, etc is pretty much always uncertain.