Insurance protects you against something which MIGHT happen.
Assurance protects you against something which WILL happen.
Hence there are 2 sorts of Life Policies, Life Assurance and Life Insurance.
If you take out a 25-year mortgage, you MIGHT die within the 25 years, so you have a LIFE Insurance policy. If you don't die within that period there is no payout EXCEPT that some policies are linked to a savings scheme (endowment policies) when you get a return at the end of the period, provided that you didn't die.
If you want to make sure your dependants are financially OK after your death you take out a LIFE Assurance policy, because you WILL die sometime and then your policy pays out.