I understand science, but it's never explained how the universe got it's start, that it just happened or that it was created, which is a more logical explanation. Some theories that make sense to some, and we use faith. I wouldn't threaten you with eternal damnation. That's God's to judge. All I can do is say he exists, and you'll make your choice. We'll all meet God when we die, and for some it might not be a good time.
The devil has no power. He's just waiting for us to make the worst mistake, turning our backs on God.
God might have some strange reasons bad things happen we can't understand, and I'm definitely one who questions why, , but again, in simple terms anyone can understand. 80 years or so is nothing compared to forever, and any deity that can create the universe from his mind surely has something worth waiting for when we pass, with no pain or sorrow, and only the good things we've come to enjoy, and then some.
As believers we can only hope those who don't believe can see different, as there are a few reasons people turn their backs on God, one being they lost someone to some stupid disease, and can't understand why God would allow it, or their parents forced religion down their throats, and maybe in abusive ways, and this turned them against God as well. Why would God allow children to suffer? All these reasons come back to that 80 years or so, and it still doesn't add up to forever. Someone who thinks they are above all this, that others who believe are naive or stupid, will talk to God someday, as we all will.