Intention

I am confused about how the saying goes. Is it "the road to hell is paved with good intentions or the road to heaven is paid with good intentions?" What is the reason I ask? Well, I have discovered what "intentions" are. They are what motivates us to do things. If you are not motivated to do it you will not do it. Example: I had every intention of going to that party, but time got away from me. First off if was a priority to you, you wouldn't have allowed time to get away. Second: If that party was of interest or a desire you would have been there. Intentions in truth come from the heart. So to say you intended to do something you are saying you are doing it with love. A better way would be to say it is "I thought about it" or "I meant to". Unless it truly comes from the heart. Than it is an intention, and every intention is followed through on. So it is my belief that if the saying is " the road to heaven is paved with good intentions". Than are perception about it is wrong.How so?
I let you think on that.