Ok, a "better" phrasing might be "good intentions do not guarantee good results, nor do they remove responsibility for bad results".

Bad intentions, on the other hand, are sufficient to make you [can't think of the right word, not responsible, maybe liable?] even if the results were good.

That has actually *happens* btw, I recall hearing about a number of instances where someone's bad intentions lead them to do something that turned out to *help* the victim.