Who are the RS players in this? The character accused of cheating and the best friend? If so, you need to look at the attitude of the relationship itself for best results, not just the attitude of the angry friend. So instead of the best friend accusing the other character of having an affair and having an attitude about it, it should be something like:
Attitude Gist of Being Candid or Forthright
Character 1 "We need to talk about something. Every time my wife has to stay late at work, you can't go to the bar and hang out because of some dumb excuse. To be honest, I think you're sleeping with my wife."
Character 2 "I can't believe you'd just come right out and say something like that. I don't care for you much right now"
C1 "Just tell me the truth, dude. We've been friends a long time. I can handle it. Did you or did you not sleep with my wife?"
From here C2 can say "yeah, I did" and the candor can drive the friends apart, or C2 can say "no, I didn't" and the lack of candor can drive the friends apart.
I still struggle a bit with RS, so that's probably not the best example. And I'm aware the the dialogue is poor, but it's just an example. Haha.