This applies to love for people OUTSIDE your immediate family
LEVEL ZERO:"I am interested in this person and they attract me. I would not like to see them unhappy and will try to make sure I do nothing to upset them" Liking rather than love. The feeling you have for a)most of your friends or b) someone you would like to know better, this feeling holds the potential to build into love.
LEVEL ONE:"I care about this person, and their happiness matters to me. If I have an opportunity in my day-to-day life, to make them happy or to avoid them being hurt, I will take it.". The feeling you have for close friends, new boyfriends/girlfriends you are just learning about, a lover as the affair draws to a close, or an ex-lover of whom you are still fond.
LEVEL TWO:"I care deeply about this person, and their happiness is important to me. I will do whatever I can to make them happy and to protect them from pain, even if it cuts into my time or interferes with my plans." How you feel about your best friends, an established partner who may not yet be your lover or you do not yet feel fully secure with, or a long-term lover you have decided will probably not be your life-partner
LEVEL THREE:"This person's happiness is as important to me as my own. I am hurt by their pain especially if I have caused it. I will actively seek ways to make them happy, and will fight to shelter them from harm." Love at its height. The feeling life-partners, and new or newly established lovers, have for each other.