If a stranger approaches you and says they know your buddy “John”, but all their facts are wrong concerning him, you could safely conclude they are referring to a “different” John.
With that in mind, there are many religions that claim they know and believe in Jesus, but that doesn’t mean they are referring to the same Jesus of the Bible.
For example,
Mormons believe Jesus was the spirit brother of Lucifer. That's not the Jesus of the Bible.
Jehovah Witnesses believe Jesus was Michael the Archangel. That's not in the Bible!
Muslims believe Jesus was just a prophet. That's definitely not what the Bible teaches.
and Bahai teaches Jesus was simply a messenger.
Notice how none of these religions teach what the Bible says, that Jesus was God in human flesh.
You see, the real Jesus sparked more controversy than any other religious leader in history. He made radical claims, spoke, not from, but with authority, and forgave people of their sins; which was a hook that God alone could hang His hat.
He healed without medicine, fed thousands from a boy's lunch, and calmed the raging sea.
His claims: He claimed to be the Way, the Truth, and the Life and said that no man would come to the Father, but through Him.
He claimed to be the Bread of Life, the Light of the world, the good Shepherd, the true Vine, and the Resurrection and the Life, and He was ultimately crucified because He claimed to be God.
He was able to conquer death by rising from the grave as He said He would.
How is that?
Because, He is the Christ, the Savior of the world.
So, if someone comes to you talking about Jesus, but he doesn’t sound like the Jesus of the Bible that's probably because he isn't.