Love and Lust can be categorized as such:
1. Love is unselfish. When one thinks about love (true love) it is always thinking about how it can serve the other person. It is not self seeking, self righteous or seeking to gratify one's self. Love is about committing oneself to the service of another person or persons. It will not cause one to be envious of the other person, nor will it inflict harm. It is an entity that lasts and it will remain patient throughout all of the ever changing scenarios of life.
2. Lust on the other hand is always about self gratification. When one is lusting after a person or a thing, it is self motivated, and it is based on the desire to fulfill what one thinks is a need. It does not have a regard for anyone else, nor does it cause remorse when someone has been affected in a negative way. Basically, lust does not concern itself with who it will affect, as long as the selfish desire is obtained.
The key is the action behind each. Some believe that love and lust are connected, when in reality they are completely different. One cannot co-exist with the other because one requires selflessness and the other exhibits selfishness.