After listening to a training CNTCS system in China, Mr. Rong Bin's answer is probably like this:

Theoretically, everyone is a trainer. When you need to influence the thoughts, attitudes, knowledge and skills of another person or a group of people, you are doing training. But because it is not systematic and commercialized, you can't call it a trainer yet, you can only call it a trainer. The concept of lecturer mainly lies in "speaking", and the trainer may not be able to speak well. For example, many trainers in the development category express very general ideas, but they have the skills to expand their majors; The master who takes the apprentice is also a trainer, but many of them express it in general terms. Excellent trainers have good expression skills, so they are called "lecturers", which means that anyone who is willing to pay has reached the commercial level.

A certificate is just a way to prove it. There are many ways to prove that you are a trainer or lecturer, not just certificates. Because of the credibility of China certificate, a certificate is often a fig leaf. The more you use certificates to prove it, the more you can't use forces other than certificates to prove it.