How do you view love? Is it a strong bond or just a positive feeling? Scientifically, it can be caused by the release of chemicals like dopamine, serotonin, oxytocin etc. Do you think chemical reactions would make you give up your life for your friend? What is your take on this topic?
Whether it is caused by chemicals or not does not matter atall. What matters is how you reciprocate the love. I have heard of psychopaths who love to slaughter people. What is responsible for people loving to slaughter, destroy, etc? dopamine, serotonin, oxytocin?
Now you can see real love is much more than that. It is about unconditional kindness, mercy, care, etc to anything that want kindness, mercy, care etc
No amount of dopamine, serotonin etc would make a bad person love what they hate.
The key word you said in there was
unconditional. People may mean different things when they say the word love, or speak of love, but love can only be real if it is unconditional. That means, it has no cause and no ulterior motive. It is not dependent on anything. You only love something when you value it as an end in itself, and not as a means to an end, or what it gives you, in terms of feelings of pleasure, gratification, or anything else. Otherwise, it is just utility.
Also, when the OP asked if it was just the result of a chemical reaction in the brain/body, this implies a materialistic, reductionist worldview that sees all life as nothing more than atomistic poolballs bouncing around and a soup of chemicals that somehow came together and evolved. To understand the flaw in this worldview, imagine that you were to die in the next moment. What in the chemical composition of your body and brain has changed in that moment? Atomically and chemically speaking, nothing has changed. It's the same lump of clay/neurons/etc. So the question then becomes, what exactly is animating it?