Insure and Ensure

I overpronounce these when saying them, as if to say, "I know which one I'm using. Really, I do."

To insure something is to guarantee that no loss or harm will come to it, usually by way of purchasing an insurance policy.

To ensure something is to make something certain or sure; to guarantee it.

As you can see, they're very similar. Really, to insure something is to ensure that it will be safe (or you will be provided with appropriate compensation in the unfortunate event that it meets some terrible end).

Ensure that you turn off the stove when you're finished cooking; our home isn't insured against fire damage.