To Be in Love

What does it mean to be *in* love? How does it feel? How do you know if you are?

And is it possible to be in love with someone if you don't spend a lot of time with that person, or don't know too much about the person?

I used to think that it was this magical feeling that can't really be explained in words. But a friend recently gave me a different description: that being in love is when two people are able at the same time to share love with each other. Meaning, one is fulling able and willing to receive love that another is fully able and willing to give, and vice versa.

What do you think?