It's a difficult question, that is true, but just because this is extremely sensitive territory, it doesn't mean we should avoid the debate.
There has to be a way to help people who consider they have no quality of life and want to die. I don't think anyone who has read about Diane Pretty or the other lady on a ventilator could think they are being "manipulated" by others. There needs to be a system with plenty of checks and balances, where candidates need to be assessed by several independent doctors, psychiatrists and other pertinent professionals, and apply to the courts.