I'm a certified Toyota technician and a certified pre-owned cars are thoroughly checked over having to pass every check on a very detailed check sheet with strict guidelines. It's guaranteed to be as good as new with nothing at all wrong, from inside car to tires and drivetrain signed off by technician. And you do get a warranty with it.
The difference between a certified pre-owned car and a regular pre-owned car is one that is certified has passed a safety inspection and comes with a warranty. Often times these cars have been traded in like new condition and it's a way that the car dealer can charge more for it as a result.