I think the best replacement would we way or idea.

In English, proverbial phrases such as this sometimes prefer to use simple language. Because of that I would probably prefer "way" with Justin. That said, "benchmark" works fine but in my opinion it makes the tone of the sentence sound less proverbial and more matter-of-fact.

I got it. Thank you Lou.

Hi Simba! I hope you're well. Yes, benchmark is a suitable substitute. I also think you could consider the collocation "reference + for + verb + ing." In this instance, the phrase would be: You would have no reference for understanding what it means to be happy.

Thank you.