In the end we give too much importance and meaning to single words like "happiness" "love" "joy" instead of just understanding the feeling they come from..
Do you mean "honest with ourselves"? Because I believe also there's not a single truth, but there are as many truth as consciousness, but everyone has just one truth that is true for himself.
I don't believe anyway happiness is an illusion, but for sure is not something static, that you could just achietand hodl without doing anything, happiness needs constant effort.. probably the effort to be honest as you said.. 🍀💜🫂