What made us believe in love

I've been wondering what was it that made us believe in love. We seem to believe in it for no reason, even before we know what it is. But how come?

The Little Mermaid seems to be hinting at the answer: we are told to believe in it since childhood when we could not possibly know what love is, and when we were not yet able to cast any doubt on what we are taught and told. So, in love we believe.

Yet we may have lost some of the meaning in such motion pictures. Surely, they give more than a simple and groundless belief.

It tells about what price we pay for true love, and what true love requires. Love is only reached on the basis of love, more love from more people.

What if the little mermaid followed the king's demand in order not to offense him instead of keep annoying him and persisting in her adventure to the human world?
What if the little fish refused to follow her in all the ventures?
What if the bird didn't help and encourage her?
What if Sebastien the crab conductor refuse to change his stand to help?
What if the princess feel nothing toward the mermaid since she has lost her beautiful voice?
What if the king of the human world didn't approve their marriage?
What if the ocean king didn't sacrifice himself to save the mermaid from the witch?
and What if the mermaid and the king won't live happy together afterwards?
……
So many possibilities, so many obastacles and ordeals.
Love is only love, it does not spell happiness itself, let alone hapiness for a lifetime.

It's true that motion pictures like this tells us to believe in love, yet they also show us all the difficulties on the way to true love and to the happiness of life. A belief in love, virtually, does not simply mean that you believe that the right person will one day come. It also means that you have to keep your faith in it in all those difficulties and hardship, and that you keep your faith not only till the day you get married to the right one, but also, through all your life with him, whatever may happen.