What exact is whole life insurance, and how do life insurance companies profit from selling it?

Agents are always extremely keen about selling my family whole life insurance instead of term. According to the agents, whole life is preferable to term since it does not expire and as a result the beneficiary is guaranteed some payment upon the death of the insured. However, why would the insurance company profit from such a setup if they are bound to pay back an amount that is at least equal to the total amount paid?

I have tried to do some research on my own, but I still can’t seem to fully understand this matter. Any help will be greatly appreciated!