How do you differentiate between Love and Lust?

I personally think that we all know the difference, that lust has to do with desiring a person's appearance for sexual pleasure, whilst love has nothing to do with that. But our main challenge is how do we spot the two from a person you just met?

My own opinion, it takes patience to see that difference.
A person who lust after you can take you out, buy gifts and play every role of a lover...

But these will only last until they get what they want.

That's why I believe if you make them wait, it will really test and reveal their motives. Lust is not patient.

And I also believe that maybe the no sex before marriage principle was was meant to clear that confusion. Can someone who only wants to hit and run wait?

Your opinion is welcomed.