I tell them the truth. It's not easy, it's not cheap, it takes practice and training because it's a skill to be learned like many others they have acquired as they have grown through the years. With that said, it can be done and for most it is worth the effort. I tell them they will crash sooner or later and they will feel bad about it but there is another plane waiting for them to go on with. At that point I stop and see if they have any initial questions. After answering those I go on to explaining costs and training programs available. If possible I let them try flying a trainer on the field the same day before they leave. Gotta "set the hook".