That is probably one of the most heavily chemically driven attractions I would say, even. There is a very high evolutionary demand for stopping people from abandoning their screaming, smelling, sleep depriving child.

If you're including neurochemistry, then doesn't that mean everything is reality according to the OP'd definition?

Well uh.. yeah that's an excellent point. I suppose it would make everything real since otherwise it wouldn't exist at all.

If we make the hard distinction with subjective experiences vs. objective observations, then I suppose love isn't real. But there are still people and animals doing actions that objectively count as love regardless of their subjective experience of it. I suppose it again depends on the definition. Like, if you had a bunch of robots programmed to act with deep affection towards each other, does that qualify? I'm not sure.

In the given example you may choose to believe that slapping others' children is acceptable but when you do so you're going to experience physical violence and no amount of belief is going to change that.

In this manner, love is real because the consequences are real.