An Auramancer can sense peoples Auras via dice roll. You should roll Sense Motive (State Sense Aura) and in return they are to roll Deception/Bluff. They should give a hint to their Aura (however elaborate they wish to be) if they lose the roll.

 Aura detection examples could be: Detecting hostilities within a room, detecting people nearby such as those creeping around the vicinity, detecting peoples levels of corruption or detecting general feelings of a person. 

It is unlikely that someone who is 'incorruptible' will be able to have their aura sensed, but you can dice roll regardless and they can choose whether they want to roll in return or reply 'undetected'