How to guarantee corner cases in property based testing

Recently, I'm quite excited when reading about the idea of property based testing.

But I have 1 question that I still cannot find the answer anywhere:

How can property based testing ensures that it will test the corner cases every time?

To be more specific, let say I'm using ScalaCheck to test my division function:

def divide(a: Int, b: Int): Int

As the test cases will be generated randomly, how can I be sure that ScalaCheck will check the case where b = 0 every time?