Haha I enjoyed this a lot as well 
Regarding our case at hand, I guess Akechi is so confident because he is the one who swapped Sanae for the double? As we still don’t know who hired her, or did I miss that one? 
It was just that one chapter, and ever since we are left in the dark as to who was that and what happened to the swap. First I thought it might have been Iwase himself, to protect his daughter, but all points to Akechi right now.
