Extension of probation only means 2 things: you dont meet expectations or your boss dont like you. Either way, its not good for you. So you must be open to find out where you fail and learn from it.

No one in this world want to lose good employees. So if he/she is good, for sure they will confirm them as permanent employee asap, some even have early confirmation. Just ask yourself, if you have a good employee, wouldnt you do the same too?