This is a question often asked, and the short answer is, He doesn’t.
God is perfectly loving, and He would prefer that nobody be lost, but He granted us all free will, and many people CHOOSE their fate. They CHOOSE to do things which are bad for them and/or bad for God, and those things MUST be punished. God is perfectly holy, and this makes it impossible for any sin to approach Him. So unless a person is completely without sin, or has all their sins already paid for, that person has no place to go except into the abyss. Yeah, from our point of view this system seems to be really bad, but our opinion is of no importance in this matter. Only God’s opinion is of importance.
This leaves us with exactly three choices, but fortunately, there are choices. The first choice is to never have sinned, not be sinning right now, and never sin for the rest of our life. Good luck with that one. As far as I know, only one person in all of history has managed that, about 2000 years ago. The next is to accept eternal punishment. Certainly easy to accomplish, but sounds like a really bad choice, which once you find out how bad a choice it was, can no longer be recovered from. The last choice is to pay for all your sins.
The latter sounds like the best choice. Unfortunately, there are conflicting ways this can be done being proposed, and it seems likely that choosing the wrong one leads to catastrophe. Let me suggest that the scripture which shows that God is perfectly loving and that sin separates you from Him, is the only reliable source of of the way to ensure your sins are expunged so that you are neither punished nor separated from God. That forgiveness for your sins is a free gift of God available to all who will accept it. This is documented in the New Testament of the Bible; check into it.