I’m being very specific for a reason. I think I have a clue what family bond love is, but I don’t think I had experienced any type of romance in my 34 years of life.
I’m aware this answer will vary, but that’s why I’m expecting diverse answers and then I could make a sum of all of them, reaching an average and then distillate a final conclusion.
It’s different for everyone, but if someone gets in your head in a way that the first thing you think when you enjoy something is that you’d enjoy it even more if they were there to share it with you, to quote the big pizza pie, that’s amore! Or rather, it’s romantic feelings that are fertile ground for full blown love to grow from.
From there it’s all about how your emotions feel to you.