This is a serious post and not a sarcastic one. My guess is that a lot of folks here believe in God and could provide Che with an explanation, but you may just be the man to do it and do it well. You really piss me off sometimes, but I have little doubt that you have a soul and a strong ecumenical core.
As che and you have asked, I shall try. I will try and be brief but I know...TLDR, LOL!
I am the same as all of you. In fact, I am in some ways probably worse. Remember if you will, the Pharisees say of the Nazarene, "Who is he to tell us the Scriptures. He's just a carpenter's son"...I am not even that but I know what is required and when I could no longer give it in truth, I set aside my faith and admitted as much to all.
Some friends were no longer friends, even those that were atheists. Faith is hope. You have heard it said that you cannot make a leap of faith in two jumps? That is true. Unless you have someone there to catch you between the moments of hopelessness and hope.
For many, that someone is the Nazarene. Jesus does not want your money. He does not demand anything but rather asks that you give what you can when you can. He asks that you live your faith, not just speak it as rote. This talking "faith" is what many churches do and talk in itself isn't what is cheap, it is double-talk that cheapens the profession of faith.
Do what good you do in private so that no one knows but you. If God exists as the Nazarene taught, your reward is knowing that you did good for someone in need. If not, then at least you know that you did something for someone without the slightest bit of wanting something in return.
In like fashion, even if you do that which is wrong (and there is right and wrong), know that you may be alone but you know what you did was wrong. If God as the Nazarene taught us exists, then he is more than aware of your transgression. But forgiveness is there for the asking so long as the asking is true. What was that song, how can there be any "sin" in "sincere"...
Some folks don't like what Jesus said because the meaning sometimes condemns how we want to live. But while muslime profit said "submit", the Nazarene says "choose". Free will to accept or not. Yes, if the Nazarene is true, then there will be judgment at the end of all things. But the muslime profit just says submit or be killed now.
Some people need to have faith in a power greater than our own. This is way there are idiots that follow creatures like Jim Jones or the Purple Sneaker Idiots of a few years ago. Even the apostles were aware that people would become sheeple and warned against being a "follower" of them. They adjured believers to follow the Christ, not them. Not any man. Just the Christ.
The proof of faith is in the living by it. Yes, we all slip and fall or as they say, "backslide". But there's a difference in being mortal and being a total liar. A Man would admit his sin to himself if not to his God. He would not shout it from the rooftops nor the street corners. As with good deeds that are righteous, the unrighteous should be kept to himself and again, if he believes to his God. And should not be repeated. Why?
Because the Nazarene said to the woman caught in adultery (funny how the Jews did not catch the man she committed it with), "Go. And sin no more" not "Go and sin some more". Faith is not a "crutch" for the weak. It is more a guide dog for those that can see but sometimes choose to close their eyes to what is righteous.
This is just how I think. It may be insufficient but it is from my experience in this life. I could go on but having to make certain I didn't make too many spelling errors on this long a post is tiring.

As is my way, in all ways and for always, be well.