Another parable put he forth unto them, saying, The kingdom of heaven is likened unto a man which sowed good seed in his field: But while men slept, his enemy came and sowed tares among the wheat, and went his way. But when the blade was sprung up, and brought forth fruit, then appeared the tares also. So the servants of the householder came and said unto him, Sir, didst not thou sow good seed in thy field? from whence then hath it tares? He said unto them, An enemy hath done this. The servants said unto him, Wilt thou then that we go and gather them up? But he said, Nay; lest while ye gather up the tares, ye root up also the wheat with them. Let both grow together until the harvest: and in the time of harvest I will say to the reapers, Gather ye together first the tares, and bind them in bundles to burn them: but gather the wheat into my barn.
And the answer to your questionIt is sometimes difficult to tell whether or not a person is really saved.
Tares:Zizanion{Gr.}or darnel,which are false converts. Wheat and Tares bear a striking resemblance, but tares do not come to fruition. Do we have to wait until harvest is ripe. It may be difficult t find out whether he or she is a true convert, but Jesus said:Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles? Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit. A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit. Every tree that bringeth not forth good fruit is hewn down, and cast into the fire. Wherefore by their fruits ye shall know them.
Matthew 7:16-20
Overall I am really not sure on this, I think we should consult the other members in the Christian hidden forum. But I believe that you have the answer.
God Bless brother in Christ