true love, as i have said many times here over the years, is putting up with someone at his worst, letting him see you at yours, and deciding that there is still a strong enough bond to get past the WORST, not the best. and that, in and of itself, will lead to dysfunction, so there has to be more than a little constant stream of good to keep the bad from becoming overwhelming.
and how are you going to know any of this by looking at a person? i believe in lust at first sight. there's nothing wrong with that: initial attraction is often needed to spur the rest into motion. however, i do not believe that the thunderbolt itself is love. i believe it is an intense call to action, but love (biologically speaking) grows within the brain in time. there are people who had an intense connection initially, and their affection remained and grew deeper... but they weren't in love from the first moment. that isn't possible.
what you have described is infatuation and/or desire (eros). but there is the need for mutual affection (anteros), or else there is no long term reciprocity.