Here's how we can be sure that we know God in the right way: Keep his commandments.
If someone claims, "I know him well!" but doesn't keep his commandments, he's obviously a liar. His life doesn't match his words.
But the one who keeps God's word is the person in whom we see God's mature love. This is the only way to be sure we're in God.
Anyone who claims to be intimate with God ought to live the same kind of life Jesus lived.