I thought the meaning was really obvious. Is it the "Get nothing less than you deserve" part that throws you off? I think technically this means that you will get at least what you deserve, and not less, but people are stupid and don't realize what their words mean half the time when they open their mouth.
It says almost exactly what it said, that if you are an unpleasant person, then the romantic experience you receive will be exactly what you deserve.
I don't like that phrase very much. I'm a nihilist, so "deserve" has no clear meaning for me. At any rate, love is something someone has to give to you, and people are dumb as s**t a lot of the time ("dumb as s**t" = methaphor), so even if, for instance, you defined "deserving" as being what the other person is looking for, being "deserving" does not mean that you are going to get it, although there is a good chance that it will improve your chances.