the road to hell字面意思是去往地狱的道路，pave是铺地的意思，be paved with,被铺满，good intention是好心，良好的意图，所以the road to hell is paved with good intentions字面意思去往地狱的道路铺满了好心，其实就是说好心办坏事，想做成一件事光有好心是不够的。

【例句】
We should take a calm view of their success and not put too much pressure on them, otherwise the road to hell is paved with good intentions.
我们更要冷静看待他们的成功，不要给他们太大压力，不然好心办坏事。

She tried to help by defending Dad's position and they haven't spoken since-the road to hell is paved with good intentions.
她试图通过维护爸爸的立场来帮助他，从那以后他们就再也没有说过话-- 好心办了坏事。