CLARITY
There is an easy way to tell the difference between genuine teachers and those who only pretend: observe how they answer the questions. The pretentious ones will provide nebulous answers shrouded in mystery and paradox. The real teachers will respond in a way that makes the complex simple and easy. The difference is clarity.
There can be no doubt that there is mystery at the heart of the Tao. There are things about life, existence, metaphysics and consciousness we do not understand very well at all. This, however, does not mean everything must be mysterious and we can never know anything for certain. Just as quantum mechanics has numerous real-world applications despite its mysteries, the Tao also has practical, down-to-earth aspects that are clear and useful, despite its own mysteries.
The Tao Today
Keep this in mind: the principle is simple; the mystery is the mastery. Beware of those who try to convince you that the Tao is unknown and unknowable. Real masters are ones who understand the subject matter so well that they can explain it in the simplest possible terms. This is true for the genuine just as it is for the real experts of any discipline. Look for this kind of clarity in those who would be your teachers.
The Tao of Joy Every Day
~ Derek Lin