Matters of the heart

Have you ever done a self evaluation of yourself? Recently I sat back and tried to look at myself as others do. I looked at me from the outside instead of the inside, and I learned a few things. I learned that I am a lover and a fighter. I love hard and I fight harder, especially if it's something I believe in.
Someone told me recently that I give parts of myself to people who aren't deserving of it. But how do you determine who deserves your love? How do you know who to trust whole heartedly and who to pack your bags and run from? I guess those are questions for the ages.