Is "turning a good hand into a bluff" the same thing as "a better hand will call, a worse hand will fold"?

I was chatting to Renton earlier and he reminded me of a hole in my game, which is betting when I should check, especially on the river. I live in eternal fear of being bluffed, so I always tend to think a value/blocking bet is the right move. Can people who know better than me explore this further?