It is a slang expression that has a general and particular meaning. The general meaning is knowing if something is worth the trouble of trying to get it, i.e. does the reward outweigh the punishment. "I'd rob a bank if I could, the juice is worth the squeeze." A particular meaning refers to not stealing one's girl unless one is ready to accept the consequences.The juice refers to the girl in this case. Example: A: Dance with her! B : I don't know about that. Her boyfriend is tough looking. A : Man, I'd do it if I had the chance. B : Yeah, you're right. The juice is worth the squeeze.

it's mean that if you really want something you will really work to get this but will be worth

Freshly squeezed orange juice or out of the plastic container? Which tastes better? Which takes more effort? Now you have the answer.

Home squeezed juice usually tastes best, it's worth the work behind it. So it is to say hard work pays off.

To get juice out of something you have to squeeze it. And that means work. Extend that image to whatever you want, and you have the meaning of this expression.