Originally Posted by Kangaroo Don
Sollozzo couldn't even remember his own lies!

In the car
Quote
Michael: We'll straighten everything out tonight. I don't want my father bothered any more...
Sollozzo: He won't be, Mike; I swear on my children he won't be.

later at Louis' Restaurant in the Bronx
Quote
Michael: What I want -- what's most important to me -- is that I have a guarantee: No more attempts on my father's life.
Sollozzo: What guarantees could I give you, Mike? I am the hunted one!
I missed my chance. You think too much of me, kid -- I'm not that clever. All I want, is a truce.



To be fair he didn’t really lie. The Don was never touched again and Sollozzo was the hunted one.

He pretty much laid out how the rest of his life would go (how short it was lol). Sollozzo was cocky enough to think he could negotiate his way out of killing the Don while laying the blueprint of The Corleone’s Revenge