Why did Jesus have to die for our sins? Why couldn't have God just forgave us?

I'm agnostic. But i'm trying to make sense out of God and Jesus. Which so fair it doesn't make sense to me lol. --Kai,so like if this is a fallen earth and the earth isn't perfect,and we live on the earth and like duh everyone is going to commit sin,why didn't ''God'' just forgive his people? And what about the people before Jesus died for sins. Like what,did they just go to hell dying before they had the chance to repent? --And... In my view,okay so if ''satan'' is suppose to tempt us and try to get us to do bad stuff,then he is the reason we aren't perfect. Sooo... Why would God make him to purposely tempt us? And then make Jesus die,for what satan will get us to do. Why is God willing to lose to many souls then just have had us all in heaven? It's like... You first make thieves and then punish them. If/when i have have kids,i wouldn't try and test them or purposely put problems In their way to mess up. Why did God make his ''beloved'' son die for us,when he could have just forgave us period. What's with the non unconditional love?