If I needed driving directions from Miami to Chicago someone could give me a "real" paper map. But, what if the "real" map labeled Philadelphia as "Chicago" and the arrows and indications actually took me to the Land of Cheese Steak Sandwiches instead of the Land of Deep Dish Pizza? It would be real but not true.
If I followed it I'd end up in the wrong place! Being "real" is not enough.
What if the person who made the map was sincere, and genuinely thought that the map they gave me was true? Would that magically transform the errant map into a true one to Chicago instead of Philly? Not at all.
God's word, the Bible, says it is the same with the spiritual experiences of other religions. There may be "real" experiences that are not true in that they don't lead to the One true God. They don't lead to the way of life God has provided at the cost of His only Son, Jesus.
Here is an amazing passage in the Bible that points out the difference between "real" supernatural phenomena vs. "true." Deuteronomy 13:1-3:
If a prophet, or one who foretells by dreams, appears among you and announces to you a sign or wonder, and if the sign or wonder spoken of takes place, and the prophet says, “Let us follow other gods” (gods you have not known) “and let us worship them,” you must not listen to the words of that prophet or dreamer. The Lord your God is testing you to find out whether you love him with all your heart and with all your soul.
Notice two things in this passage: 1) the sign or wonder, the miracle happens! It is real; and 2) the person performing that supernatural sign then says, "Let's worship a false god, come on!" It is a "real" supernatural phenomenon, not a parlor trick, but it is not "true" in that it leads to false gods.
Also note that God actually says He "allows" this to "test" the Israelites to see if they will follow His word despite things that are "real" happening that are nevertheless not "true."
Proverbs 16:25 says, "There is a way which seems right to a person, But its end is the way of death." It seems real, but it is not true, and even leads to eternal separation from God, spiritual death. It is a mislabeled "real" map!
Christianity is about a faith relationship with the one true God. But there are countless counterfeits. Just like a counterfeit $100 bill is printed on "real" paper with "real" ink, yet it is not true. We must be guided by God's word. Feelings, words, experiences, strange unexplainable things, or even "real" supernatural happenings can be used to mislead us.