Can the victim of a failed Balserph resonance attempt tell what just happened?
With a successful Detect Lies (or if the truth of the matter is obvious), the victim can tell a lie has been told, but not that anything supernatural has happened. A Seraph might detect it on a Resonance roll of 5 or 6. (Infernal Player’s Guide, p.27) If someone resists the Balseraph’s lie, that’s different; someone aware of Will-based resonances will probably realize something supernatural happened.