Love vs Illusion scene - Al + Monks 'bet'

I love movies, love watching for fun and also for meaning - example, a specific scene has a meaning but doesn't come right out and say that meaning, it uses dialog or actions to show us the meaning....usually romantic comedies or young romance movies like this are just fun movies with no deep meaning however the scene I'm questioning is either a bad scene or shows meaning that I am not catching!!
My question....when Al, Cyrus, Monk, Eddie and Lana are all drinking and talking Al is saying how he is in real love, describing how he feels when Cyrus jumps in saying it's a hoax, it's created by a chemical reaction etc and she knows this because she majored in bio-chemistry....Monk agrees saying all romantics are simply addicts. When Al doesn't buy it and defends his belief in real love Monk suggests a bet or test if you will. He then picks up one of two identical bottles of wine saying 1 is love and the other is illusion - he pours some from one bottle into a wine goblet and some from the other bottle into an identical wine goblet (which they are very cool wine goblets!) and tells Al to pick which one is his so called love - they decide on a wager, walk over to the piano where Al tastes one and then the other - he chooses the 2nd one and Monk states he is incorrect, the 1st one is love and he chose illusion. Now here is where I am confused because there is no way for Al to determine which was love as they were the same exact thing, drinking them would not allow anyone to pick the correct one as again, there are no differences between the two! There would have to be something different about them, like picking Coke over Pepsi, if a person claims they prefer Coke and another person says there is no difference and they bet on it there could be a winner as there is a difference to most people - yes, some don't think so but that's the point, a true Coke lover knows the difference and can pick it out. So now what was that scene supposed to prove, did I miss something about the bet/game? I played the scene from start to finish to see if I missed something and I didn't, there is no way it was a legitimate choice.....now I'm not trying to be all deep, as I said, I know this isn't a deep movie which is my point, it should be spelled out! If Cyrus and Monk wanted to prove there is no real love then give obvious examples, cheating, one partner choosing to move out of state for a job and breaking up instead of staying, things like that where it's obvious. Did anyone understand how the bet was supposed to prove them right? Just thought I'd ask since I didn't get it which made me feel the scene didn't belong in the movie?! Thanks for any input!