I think it's perfectly clear that Sollozzo is still going to try to have Vito killed one way or another during the restaurant chat between him and Michael.When Michael says that he wants a guarantee that there will be no more attempts on his father's life,Sollozzo says that he can't give one and only wants a truce.This was the key part of the whole discussion----it confirms beyond a shadow of a doubt Michael's belief that Sollozzo was never going to stop trying to eliminate Vito until he was unable to do so----A.K.A. HE'S DEAD !!!! I know Sollozzo goes into that whole spiel about being the hunted one,missing his chance,etcetera,but his initial reflexive answer revealed the truth.Michael even shows a slight hint of recognition(great acting,Al)upon hearing this.The conversation is over at this point and Michael is determined to get it over with as quickly as possible.