You only think that God understand negativity and evil!I think god understands negativity & evil is inferior overall to positivity & good.
Why the uncertainty about God? Either God is good or he is not.
Evil is the absence of good, just as dark is the absence of light.
God did not create evil, but in permitting free will he allowed that beings could choose to reject good and become evil.
As to why God permits evil. We simply do not know all the ins and outs of the history of life in creation.
We don't know how events will work out.
We have to trust God.