When I say 'I won't hurt you', it's a promise, which can and will be kept but it does not come from me without a breakdown of what it means. It does not mean we will never disagree, nor does it mean that you will always like everything which I say or do. It does not mean that you will never hurt yourself by behaving in a way which is damaging to a relationship or by behaving in a way which would ultimately result in my withdrawal from your life. What it does mean is that I can promise all that I expect in terms of loyalty, honor and respect. It means I am faithful. It also means that I will not intentionally or carelessly behave in a way which causes upset or doubt. It means, at the lowest level, 'You will break these terms before I do.' Communication is essential. Trust is paramount. Be completely honest and don't make promises that you can't keep, that's all.