How to Reject a Guy Who Loves You...

How to reject a guy who loves you, he's not a christian not i'm not interested in him, what should i do now to make things right? Should i be friends after rejecting?

Be honest with him and be kind. You could pray for him and invite him to church or other Christian activities. But don't be too close, as it's often the nonChristian who influences the Christian, rather than the other way around. Although it's not easy and it's not nice to hurt someone, it's always best to put God first and obey Him.

Is It Bad To Have A Boy As A Best Friend?

It's not wrong to have friends who are boys. But if you're a teenager or older, it's not wise to have a boy as a best friend. Unless you would want to marry them! I have seen people who have had close guy friends who insisted they were just friends, and now they are married. So often either it turns into a serious relationship and marriage or only one starts to care and it causes a lot of hurt.
So it's best to only have a boy as a best friend if you both have marriage in mind. Remember to pray much about relationships and ask for God's wisdom. He knows the right person for you and can save you unnecessary hurt.