He was addressing a gathering at a yoga camp organised by Maratha Vidya Prasarak Samaj (MVPS).
"PM Modi had given an assurance that black money stashed in foreign bank accounts would be brought back. He will definitely fulfill his promise, although it may take some time," he said.
Modi wants to create a stronger India, which is not possible without people's support, he said.
Lauding Modi's efforts over UN's declaration of June 21 as International Yoga Day, Ramdev said, "Yoga will become a pillar of support for the world as it is beneficial for the health and mind of human beings.