It is said in scripture that Jesus has endured all, he has suffered all things. And as such he knows the strength needed to endure such trials. It is also said that the Lord shall not suffer you to endure things which are greater then your ability to endure.

So simply put, God knows all, knows what you can handle... So if you at some point can't figure out why you are suffering something, and you don't have faith that you'll make it, remember God has faith in you.