Is your question “Is hypnotism real?” or is it “Does it work for quitting smoking (or weight loss or whatever)?” If the former, yes, a person can really be hypnotized. If the latter, yes it can, but it has a lot to do with the desires of the person. You can’t make a person do something they don’t want to by hypnotizing them, but you can help them to modify behaviors that they want to modify with hypnosis. It’s an excellent therapeutic tool. Your details indicate that your ideas about hypnotism may come from popular media and urban myth.