Eckhart Tolle discusses the limitations of using willpower for manifestation, suggesting that wanting something implies a lack of possession. He advises that the most effective way to manifest is by feeling that you already possess what you desire, which arises from a sense of completeness and presence in the moment. Eckhart Tolle emphasizes merging desire with a sense of fullness and being, creating a powerful manifestation environment where happiness is not dependent on external achievement.