But ”but I thought you thought so too? Poirot gave me one look, which conveyed a wondering pity, and his full sense of the utter absurdity of such an idea. 
I was so sure that Poirot and I were following the same idea, but when I said as much, he gave a look that set me straight. 
Poirot complimented me on my great idea that resulted in solving the mystery. 