He has a prophecy for you? Does that make him a prophet
i think not.
He should read this scripture and think about it alot before he makes such a judgment about your heart (which he cannot read):
1 Corinthians 13:
4 Charity suffereth long, and is kind; charity envieth not; charity vaunteth not itself, is not puffed up,
5 Doth not behave itself unseemly, seeketh not her own, is not easily provoked, thinketh no evil;
6 Rejoiceth not in iniquity, but rejoiceth in the truth;
7 Beareth all things, believeth all things, hopeth all things, endureth all things.
8 Charity never faileth: but whether there be prophecies, they shall fail; whether there be tongues, they shall cease; whether there be knowledge, it shall vanish away.
I dont know all about your heart but i have seen from your posts here that you dont have a dark heart nor do you come across as fearful.
Dont trust this assessment from him about you, you are saved and you know it and even if you doubt it God sent His Son the Lord Jesus to die on a cross for you sins and that is Fact and you know it and your saved.
Hebrews 13:
5 Let your conversation be without covetousness; and be content with such things as ye have: for he hath said, I will never leave thee, nor forsake thee.
John 10:
27 My sheep hear my voice, and I know them, and they follow me:
28 And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand.
29 My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father's hand.
30 I and my Father are one.
Maybe this prophet dude has forgotten this commandment from the 10 commandments:
Exodus 20:
16 Thou shalt not bear false witness against thy neighbour.