An eternal question ... I used to think it was something you'd never know until you actually found it, and then you would simply just know! ... but this leads to the question of how would you know that, that is it, and I've never quite been able to answer that part ... so I'll take another approach...
"Love" is something with many definitions, I mean there is "brotherly love", "love for friends and family", "unconditional love", and the list goes on ... so what do we really mean when we say "love" ... I think in the general case if we are trying to define it, we mean "unconditional love", whereby you love a person regardless of their failings.
I see it like this, "love" is where you think and feel a certain way about someone. It is where their words and actions become sacred to you, and you can't live without them. They effectively become a part of what makes you up, and you would do almost anything for them. But most importantly, true unconditional love, is simply that, unconditional ... and no matter what they do, as bad as it may be, and as much as you may disagree with it, you still feel that way about them.
I know the topic of "love" easily turning to "hate" has come up before (
Can you fall out of love?), but I think my explaination on this stands, "this is still love, because in this case the reason you hate them is because you still love them, and anything bad they do hurts you in a way only someone you love can." Hence I believe, in this situation, you still feel all the aspects of love.
© Ole 2004