riddle of two paths

this riddle had me wracking my brain for awhile.

honestly as i’m writing this, i still have yet to figure it out.

you reach a fork in the road and one leads to happiness while the other leads to sadness.

there’s a troll on each path, that looks completely identical. they talk, walk and act the same. no telling the two apart.

however, one only tells the truth while the other only lies.

and you can only ask one question to on of the troll.

who, and what will be the question you ask?

this was first heard from the Linking Your Thinking with Nick Milo – This Secret Principle Will Transform Your Notes talk