From the Getting Started FAQ page (I added the italics in the quote for emphasis on why you would need a commercial ("professional") API:

Is there a commercial service? Yes. You can contact our sales team by emailing info@themoviedb.org.

What is the difference between a commercial API and a developer API? A commercial API is for commercial projects and a developer API is for developers. Your project is considered commercial if the primary purpose is to create revenue for the benefit of the owner.

Disclaimer: I'm not a TMDB API Support person. I just read the FAQs and have seen a few of these questions on this forum before.

People love to watch movies and series soo u used that api to my site and they will pay me for that premium movies

@shimul122 said:

People love to watch movies and series soo u used that api to my site and they will pay me for that premium movies

As already explained to you here, a professional API key will absolutely not allow you to play movies.