What is the ruling on someone saying: "It's as if you know what I'm going to say"?

There is no harm in using the phrase "It's as if you know what I'm going to say," for it contains no legal prohibition (in Islamic law) nor any claim to knowledge of the unseen. Rather, the use of (as if/كأنّ) negates that. The speaker's intention may be known through sagacity (firasah) or through information from a knowledgeable person.