You have no idea. While telling someone about the Lord recently, his only argument (the only one he could come up with) was that because the Gospels were not written in modern day parlance (written as we would a modern day novel), they could not, therefore, be genuine. He was serious. I was disgusted and amazed.
The Lord’s commandment was to take the Gospel to all the world. He did not say that everyone would believe it. Once heard, it is up to the individual to accept it or not. They are, then, responsible for their own salvation. You did what Christ commanded. His salvation is not your responsiblity, it is the hearers. God gave us all a free will.