Insure versus ensure used to bother me but I have let go of the negative energies emanating from that issue. Note that the word ensuren, in the middle of the fifteenth century, spawned both ensure and insure with the same meaning. It wasn't until the middle of the seventeenth century that insure took on its specialized meaning(s), and even today it does not exclusively entail those meanings, e.g. it also currently means "to guarantee against loss or harm" per Random House, or "be careful or certain to do something," per Princeton University Press. Add to all that the related word assure, and the fact that insurance in French is assurance (having itself apparently devolved from the Old French enseurer or aseurer), AND the fact that assure can be a replacement for insure in Britain, and, well, you have a right mess on your hands. Fancier distinctions (such as using ensure where there is no specific insured property or event) just can't maintain their integrity.