what is the difference between "insure" and "ensure"?

[Rebecca]

Dear teachers,
I would like to know what is the difference between "insure" and "ensure" because sometimes i do it wrong in my exercise.
HELP ME PLEASE!

thanks a lot.

[Conchita]

To insure is to agree with a company that if you pay them a regular sum, they will compensate you for loss or damage to property or persons.

To ensure is to make sure of something as in 'the reviews ensured the success of the film'.

[Rebecca]

thank you for your helping me.