We cannot try to be happy. In this endeavour, trying is failing. What we can do is investigate why we are unhappy, to see how our dream of happiness depends on some person, situation or circumstance. Dependency is misery. True happiness comes from within. It already is.
So then, how to tell the difference between the true and the false, the real and the unreal? Whatever has a beginning and an end is false. All else is true. From A Course in Miracles: “Nothing real can be threatened. Nothing unreal exists.”
The truth reveals itself only when we have consciously abandoned the false—our habits and dependencies; our fears and expectations; our knee-jerk negativity and every one of the ideas we hold about ourselves.