Faith. The Pali word is Saddha. Saddha is confidence or faith, but grounded in Wisdom, because faith not grounded in Wisdom can be blind and lead us into believing things that are not actually true. The Buddha encourages a Saddha that is grounded in direct experience or in contemplation of direct experience through Wisdom. Saddha is quite important actually, but in the way we use it here, it is confidence based in experience. Usually when people come here for the first time we want them to practice the methods so that they get a confidence based on experiential understanding and direct experience. From this direct experience that the methods are working based on the Four Noble Truth, the experiential confidence or Saddha or faith arises. Then we have a much better foundation for contemplating deeper things as we go along the path and reach those crossroads of doubts, and don't know which way to go.
Sometimes we may be encouraged to go in a certain way and believe certain things that may not be true, so we have to go back again to what I said in my answer to the last question, to contemplate and use wise reflection: "Is it beneficial to myself or others, now or in the future?" This is the teaching of the Kalama Sutta, where the Buddha encourages us to use our Wisdom and put our faith in techniques and a path that leads to the benefit of ourselves and others, now and in the future.