Passion or Love

I suppose this is the question most people often ask themselves after "Do I really like him/her?"
And it is not an easy question to answer as no one really knows what love is, it has been the subject of much debate of many better writers than me and many, many poets over the aeons, and yet we still have no clue on how to define and identify it.
In all likelihood this is because it usually happens unannnounced and it is not rational in the slightest, which is why it is easily confused with passion. They both mess with our emotions, our hormones and our head.
How can you tell the difference? I don't pretend to know the answer but I can however attempt to expose my view on the issue, based on what I told my friend, and in which I genuinely believe and have believed for a while.

When you are together that you feel so comfortable that it's like you have known each other for years and you don't have to try, that's love.
When the way they speak and the way they laugh is capable of lighting up a room and that alone lights up your mood, that's love.
When just being in someone's presence is enough to make you happy and feeling content, that's love.
When you can imagine yourself with that person when you are both old, in 40/50 years time, sitting outside in the garden and you still have stuff to talk about and you are still in love, THAT is True Love.

Maybe... I think! But ask yourselves those questions, especially the last one. What do you feel?