Everyone is a real psychic, because everyone possesses and uses psychic powers (even if only on a subconscious level).
Real psychic or not, the better question to ask is whether that person treats you with sincerity and honesty. Real psychics too have limitations and make mistakes in understanding as well as communication. Mistakes are there to learn from, but intentional deception is best to be avoided.
Whether someone is a real psychic is not a question that has a yes-or-no answer. Some have progressed far along the path of the psychic; some have just started out. There are many opportunities for a real psychic to develop unique psychic abilities.
Often, it takes a real psychic to recognize a real psychic - the higher you climb, the more you can see. When there is a great difference in skill, the uninitiated perceive the psychic abilities of real psychics only as 'natural ease' or 'luck'. A real psychic knows that luck favors the prepared, and goes to great lengths to understand the psychic world.