How would you tell your student that he/she got the wrong answer without hurting his/her feelings?

I am a freelance Business English trainer and, as such, I work with young to mid-aged adults who are employed by the companies I work for. As we are all well aware of, adults show shyness in their learning difficulties and, therefore, trainers should always bear this aspect in mind. What I personally do when one of my Students is making a mistake is to look at him/her, smiling though, I give hime/her few seconds to think and then I ask him/her if he/she is sure and confident that that is the right answer. They usually re-think and give me the correct answer straight away, they feel reassured that we can all make mistakes, at times, and they end up feeling great for having been able to correct themselves before I did. I wish this is useful to you, would like to receive feedback on the issue. Thanks !