When you use ensure vs insure, the difference is important to the meaning of your writing. To communicate correctly, learn the difference between ensure and insure and you will communicate effectively. It is especially important in contracts and other legal documents to use the correct word.
Look at the sentence you are writing. Know what it is you are trying to communicate. Read the sentence out loud.
Know the meaning of ensure. Ensure means to guarantee or to make sure, safe, or certain.
For example: Betsy wrapped the glass vase carefully to ensure it wouldn't break.
Know the meaning of insure. Insure means to provide insurance coverage on something or someone. Insure can also mean to make certain by taking action and precautions.
For example: Betsy paid extra at the post office to insure the package against loss and damage.
Decide which meaning you need to use to communicate.
Generally, in nearly all cases, if you are talking about insurance, that is, an insurance policy, the word choice is insure.
If you are talking generally about taking care of something or someone, the word is ensure.