TOPIC: Prove G-d in one sentence.

If Ink spilled, would it be possible that the ink would magically spread and create a novel?

If a monkey sat with a typewriter, would it be possible for it to write a masterpiece?

If there was only a big bang, where did the complexities of nature come from? How did the marvellous world we live in come into existence? The sun, moon, stars? The millions of wonderful flowers, plants and trees? The thousands of animals?

Well the answer to that, from the atheists perspective would be evolution.
The real question for the atheists would be the origin of life problem i.e. how did the first living atom come to be?
See the book The Confused World of Modern Atheism for a complete treatment of this topic.

Ok, here is a very long sentence.
The universe runs on cause and effect, (e.g.everything that happens always has a cause as to why it happens as opposed to not happening, everything that exists always has a cause as to why it exists as opposed to not existing), and that cause also has a cause as to why it exists/happens as opposed to not existing/happening (e.g the cause of your car existing as opposed to not existing is the car factory decided to build it, the cause of the car factory deciding to build it is in order to sell it, the cause of them wanting to sell it is to make money, the cause of them wanting to make money is to pay the companies mortgage and it goes on and on) but there is a problem that an infinite number of causes that have already happened is impossible (seeing as you can't count to infinity, try counting all the past causes you also can't reach infinity therefore there are only a finite number of causes in the past), therefore there has to be a First Cause which is uncaused, which is G-D.

I could explain it in more detail but not in one sentence as requested.