"Here's what it means: the Ten Commandments are called the moral law. You and I broke the law; Jesus paid the fine. Like a criminal who walks into court, on trial for speeding, the judge says, 'Look, these fines you have are very serious, but someone else has paid them--you're free to go." In the same way, Jesus paid the death sentence we deserve on the cross, and because of that we can have everlasting life. It was finished that day. And the Bible says that if you repent of your sins, put your trust in Him, and are baptized into His name, that your sins will be forgiven and you will pass from death to life, not because you did anything to deserve it, but because of God's grace and mercy. Does that make sense?"
Explained in such a way, the message of the Gospel becomes clear. If they recognize the weight of their sin, their hearts will be contrite, and they may vocalize that they realize their guilt. Regardless, ask them when they will turn to Jesus Christ. You want to emphasize just how serious this is. One way to do so is to tell them, "What I have done today is to try and put the fear of God in your heart, because the Bible says the fear of God, the reverence of Him, is the beginning of wisdom. That fear is your friend, not your enemy. Like if you're about to jump from an airplane and fall 10,000 feet in the air, you'll put a parachute, because you rightfully fear that you will die without it. In the same way, you want to put on Jesus Christ to be saved from Hell. Does that make sense?"
If they say something other than "now" in response to your question about when they will turn to Christ, remind them just how quick and unexpected death can be. It could happen that night while one's asleep, or within the next week, or they could even die just a few minutes from then, or right at that moment. We don't know when we'll die. You don't want to pressure them here, but make sure to offer this thought, because it's a very important thing, and may indeed cause them to change their mind. Regardless of how they respond after this point, ask if you can pray with them. If they concede, then do so.