That’s because growth in character NEVER happens in the absence of pain.
Christian maturity is not something that just happens. Yes, it is God Whose power works in us to enable us to be transformed and conformed into the likeness of Jesus. However, we must put effort and desire into developing knowledge, and self-control, and patience and joy, peace, kindness, gentleness etc.
“Suffering produces endurance or patience, endurance produces the kind of character that has been through the fire and proven it’s value, and character brings about hope which does not disappoint.”
James 1:2-4 / 2nd Peter 1:5-8