This answer probably does not satisfy you because you have been brainwashed to think that it's some deep feeling between two people. That's a load of crap. The feeling between two people is a mixture of lust, phermones, and personality traits. Companies want you to believe that you have a handle on this thing called love so that they may sell merchandise. This can be anything from candy to cars.
Love is a bottomless pit of advertising.
It starts wtih flowers and candy and evolves into jewelery, then comes the houses and cars and clothes and anything else an agency wants you to buy. Believe it or not, we're not much better than any other animal, we just have the capability of confusing things. Not everything needs a reason. You don't know my name, which is of no surprise. You've probably never seen my face, but you know exactly where I live.