How do i know if apple care would take care of my phone rather than to pay full price?

You will have take care of your iPhone. Nobody else will.

Every iPhone comes with one year of hardware repair coverage through its limited warranty and up to 90 days of complimentary technical support. Both AppleCare+ and AppleCare+ with Theft and Loss extend that coverage1 up to two years and give you additional features such as 24/7 tech support and accidental damage coverage.