According to research on hypnosis, what is the most important factor for hypnosis to work?

I believe the answer is: the suggestibility of the individual who is to be hypnotized

Suggestibility in this context refers to the inclination of the person to accept the act of hypnosis that being done to that person. This would make them much more open to follow the instruction given during the hypnosis, which most likely lead to higher chance of success.