There are a lot of people in the world and more of them believe in someone other than a Christian God, if (gods) at all. Since you appear to be speaking for God, are you saying God will reject the majority of humans, from the Kingdom of God? Jews believe in God too, not in Christ as a Messiah. Other believe in god(s), just not the same God or, maybe the same, but believe, like Christians, their god(s) is/are the only one(s) that exist. If belief is a spiritual thing that is between God and those who believe, why have there been centuries of Christians trying to force people to "believe" and do much blood spilled even amongst Christans claiming their specific way to believe trumps all other ways to believe? Do you believe that God believes people who assume or expect they will be "chosen" will be chosen to inherit the Kingdom of Heaven? What do the writings of humans say God feels about vanity and humility and humans assuming to know what and who God will accept into the Kingdom of Heaven?
Once again, among Christ's final words were to forgive his killers, "for they know not what they are doing" (killing the son of God). That aligns with not helping "the least among us" as one that one does not help or turns away, may also be an agent of God, like an angel.
Some Christians keep saying he sent his son to die, while others say his son being killed by humans, showed humans NOT to kill (as Christ and the Ten Commandments reiterated.) BECAUSE they may kill, not just an innocent, but an angel or in Christ's case, the Son of God. Christ didn't die FOR the sins of humanity, crucifying Christ WAS a sin. Christ died as the result of human sin. The lesson is NOT to kill, because one might be killing someone like Christ who then "proved", according to human written scripture, he was not human, by rising from the dead.
No, it does not appear complicated, but many Christians seem to want to skew, twist, spin it to their own interpretation, force other people to believe or make them believe God will condemn them to hell and vote for sinners, while at the same time, condemning other sinners, making it perhaps, far more complicated than it is.