Instead of the target making the feat save, you do. The DC of the Disbelieve is determined by the type of illusion are you targeting. If you resist or are immune to mental effects, then you are fluent in Disbelieve.On success:You alleviate the effects of some illusion, depending on its strength.Heightened:For each additional MP spent, the DC of the Disbelieve decreases by 2.If fluent:You are adept at Disbelieve.