I will make checks for NPCs to see how convincing/honest/scary they are, but that never forces the PCs to believe or act on that information.
(NPC's Deception check, beats PC's insight check): "You're pretty sure he's telling the truth." Or better yet, "He doesn't seem to have any reason to lie, and your gut it telling you you can trust him."
(NPC makes good Intimidation check--no opposed check involved): "You're pretty sure she could snap you in half if she wanted to." Or, "If the count does call upon those favors, things could go very badly for you."
(NPC's makes a good Persuasion check--no opposed check involved): If the PCs ask... "You like this guy." Or, "You get a good feeling about this--she seems interesting to work with."
Intimidate they generally get without asking, but for Deception or Persuasion the players will generally need to ask me what sort of vibe they are getting from the person, do they seem to be honest, etc.