Q: Gurudev, how do doubts arise? How can one eliminate them?

Sri Sri Ravi Shankar: If we have any negative energy, then doubts come. Someone who is full of enthusiasm or energy does not get doubts. Doubt comes when your energy is low, when the body and mind are exhausted. When there is lack of clarity, then doubts come.

http://www.artofliving.org/in-en/what-sri-sri-said-today