True Sollozzo was cocky enough to think he could stall the Corleones to buy time, to make another attempt to kill Vito -- underestimating civilian Michael

He won't be, Mike; I swear on my children he won't be. Then What guarantees could I give you, Mike?
So swearing on his children he won't be, was a lie but then had a dose of truth serum!

I mean, this is terrible -- it's not the way I wanted things to go at all. It should've never happened. Then What happened to your father was business -- You must understand why I had to do that... Twice!

All I want, is a truce until third time lucky!