Growing as a Christian, it can be damaging to your faith to realize that some trusted Christian (even leader) you know turns out to be a fraud. It might make you feel stupid, like you were tricked, and it might also make you think that the leadership was also foolish. 

Satan is all about damaging your faith. Be vigilant, but realize in Matthew 13:24-30, God told you to EXPECT this trick by Satan. In fact, He flat-out warned us that there is a harvest, and the good wheat will have a lookalike weed (called a tare) among it. That weed is sown by Satan himself! So how can you be on the lookout so that you're not so hurt? Simple! "But when the wheat sprouted and bore grain, then the tares became evident also." (v26)

Look at the fruit that people produce. It can be good, bad, or non-existent. But don't be discouraged. That's what Satan wants.