Lyrics to a song I can't figure out

[wanderer]

I recently heard some song which lyrics sounded something like "People can only know what they're told" in the sense that one can only truly understand how someone feels if that someone expresses somehow those feelings.

The thing is I can't figure out what song is it.... I've tried google and found nothing. Any thoughts?

[Rémi]

Wow, finding the name of that song could be a good job for Sherlock Holmes!
Is the song in english? Is it old or recent? Known or forgotten?