See Mentalism is the art & Mentalist is the artist who performs this art. There are no formal courses available in India to learn the skill but it entirely based on the teaching basis. So the art can be learnt from a Mentalist itself. After a comprehensive search, the best go for you is to get Mentalism classes from Mentalist Amit Kalantri in Pune. He is one of the famous Mentalist in India. Apart from his guidance, there are not much of scope available regarding the classes for Mentalism.

You can visit the website of Amit Kalantri in order to know about the course of Mentalism:

https://amitkalantrimagic.com/tag/mentalism-classes-in-india/

I hope this helps. Wish you a great eve!