One of my favorite verses. I try to live by these words. But it is the words immediately following these in the scripture that need to be heeded in particular, "and lean not on your own understanding." Or, "your own judgment."
In other words, to follow our hearts just may be foolish.
We are not always wise and we sometimes base our directions, choices, and hopes on emotions or feelings instead of relying on the guidance The Lord provides us through His word.
If ever given a choice or a chance to make a decision go with your head (knowledge) rather than your hearts (feelings.)
With all your heart you must trust the Lord and not your own judgment.
Always let him lead you, and he will clear the road for you to follow. (Proverbs 3:5, 6 CEV)