Insure....Assure...Ensure, other than the meaning of INSURE, like getting your car insured, are they all interchangable?

From Webster's Definition of "Ensure":

"ENSURE, INSURE, and ASSURE are interchangeable in many contexts where they indicate the making certain or inevitable of an outcome, but INSURE sometimes stresses the taking of necessary measures beforehand, and ASSURE distinctively implies the removal of doubt and suspense from a person's mind."

In the United States, they are not interchangeable. I found this at dictionary.com:
insure: To provide or arrange insurance
ensure: To make sure or certain
assure: To inform positively, as to remove doubt

Usage Note: Assure, ensure, and insure all mean “to make secure or certain.” Only assure is used with reference to a person in the sense of “to set the mind at rest”: assured the leader of his loyalty. Although ensure and insure are generally interchangeable, only insure is now widely used in American English in the commercial sense of “to guarantee persons or property against risk.”

In [British] English, in finance, assurance is for something that is inevitable. So you take out life assurance; the payout is dependent on death. Insurance is for the accident or event that may or may not happen, such as with car insurance. Life insurance, strictly speaking, is insurance for a sudden death, as by way of accident, occurring otherwise than by natural causes. The form of death then is not inevitable of occurrence, though you may rest assured that death itself is.!

Ensure and assure have the same Old French root 'asseurer'. The Normans brought their form of the verb to England. Theirs was 'ensurer'. The other form, asseurer, must have come here with scholars and kings who were not speakers of that dialect; there would have been plenty of them over the centuries when our kings were French speakers; or simply come from standard French writings, in which it would have been unvaryingly used, and which all educated people would have been using.

Insure was simply, and no more than, a variation of ensure,where en- has been altered to in-, found in Late Middle English (i.e. the English of the late Middle Ages).

The French themselves use 'assurer'for all three of our forms. So we have yet another example of English being enriched by the chance occurrence of root words coming to us in different forms and our using the differing results for different, though broadly similar, meanings.

Thank you peoples!!