When you say God cannot be around sin. It means that sin must be judged, therefore, the consequence of sin is punishment. And whether we like it or not is a separate issue. You asked why you had to believe in Jesus. You don't. You can choose not to believe in Him. Jesus is a free gift. It's not because God is trying to trick you it;s, again, because sin must be judged. But Jesus took that judgement for you. As an act of mercy and forgiveness, not mention, reconciliation.
Why create Satan if God knew he would rebel? The short answer is the Bible does not specifically give the reason. It does, however, give us as humans a way out of the ultimate eternal punishment of sin, through Christ. What we can say is that God knew Satan would sin. Reason being, God has perfect foreknowledge. God is omniscient or all-knowing. See Job 37:16; Psalm 139:2-4, 147:5; Proverbs 5:21; Isaiah 46:9-10; and 1 John 3:19-20.
*It was necessary to create Satan for the fall of man. Moreover, God's plan of redemption was already set in motion, therefore, Satan was a tool by which God would demonstrate His infinite mercy. That is to say that God would die on the cross for the sins of many. And, to lay his life down for his friends thus showing the greatest love of all. (John 15:13).
* The fall of Satan provides another method by which God would be glorified. Because of His fall, God would send his Son to do something special and beyond human comprehension. He would come to die for undeserving wicked men.
*God created humans with free moral agency, giving us the ability to serve him at will. Thus, giving further glory to God by proving Satan wrong on two fronts.
1). That Satan's wicked plan would fail. Satan's goal is rebellion at all costs. Not only does he want to rebel, but he wants you to rebel against God as well.
And 2). That God's creation, some, would choose to love Him over the rebellion of Satan. And, even wicked men would refuse to "eternally" rebel against God. But that while on this earth man would struggle daily to serve Him with much affliction and unannounced pain and suffering. But even through those pains God would receive the glory through man's faithful trust in God in the midst his darkest hours.
We do not have infinite knowledge and we do not know the bigger picture of God's purposes for things. Romans 9:20 But who are you, O man, to answer back to God? Will what is molded say to its molder, "Why have you made me like this?"
* Furthermore, if God had created another being, an angel.etc., we would be asking why that angel fell. The truth is the Bible tells us FOR NOW WE KNOW IN PART. (1 Corinthians 13:9).
However, when we seek to understand God rather than doubt him, we can search the Bible with an sincere desire to learn. If God knew that Satan would rebel against him, but created him anyway, then it follows that God must have planned to use the sin of Satan as a way to complete his will.
The fact that Satan sinned does not mean that God caused him to sin or that God wanted him to sin. The Bible says that God does not cause sin (James 1:13). What we do know is that God can use sin or a bad situation and tun it around for "good."
Genesis 50:1-26; Exodus 1-2:10; Matthew 16:13-17:9; Psalm 21:1-13; Proverbs 5:1-4.
Looking at how God will bring all things together under him at the end of time, it can be said that God will bring more glory to himself by saving and redeeming a lost human race than if he had just enjoyed a peaceful world for eternity. The Lord redeemed mankind through the sacrifice at the cross, showing his generosity to undeserving sinners. To Satan, he contrasts his actions, bringing only justice to Satan through condemnation.
The cross has always been the plan of God (Acts 2:23). Christ himself spoke of the predetermined nature of his death (Matthew 20:28). The cross is God’s way of making Satan’s rebellion and following fall of man into a blessing that lasts for eternity.
For God so loved the world, that he gave his only begotten Son, that whosoever believes in him should not perish, but have everlasting life. (John 3:16).