Is it proper to use this idiom here: "...I'm sure there is more to it than that."? The sentence: I doubt it is a coincidence. I'm sure there is more to it than that. Is my sentence correct and natural with the idiom: "there is more to it than that"? If not, can you suggest a sentence with the same meaning? Thank youI want it to mean: I don't think it is a pure coincidence. / I'm not sure it is a coincidence.