Is it a sin to marry a non virgin?
No, it’s a sin to have sex before marriage yourself. You are not accountable for the sins of other people. However, the Bible also mentions that you should marry a believer compared to a non believer since light should not have anything do to with darkness. That being said, a Christian girl is more likely to be a virgin than a non Christian. However, it could be a woman who has converted to the faith and the blood of Christ would wash away her past sins making it in no way a sin for you to marry her even though she had sex with other men. Personally, my wife was a virgin when I married her five years ago. She was a born again Christian!