I'm sure that's the case for some people, but having a good heart doesn't mean you have to accept being stepped on.
Beggars, liars, leeches etc. couldn't care less what kind of heart you have, they'll still attempt to scam you.
Having a good heart, makes that right hook come out a little quicker.
A person can have a good heart without being naive.
Not really. There is no doubt though, that some people who perceive someone as having a "good heart" often mistakenly think they are an easy mark for whatever deceit they are selling.
I have a good heart but I don't attract leeches and low lifes.
Mostly you are right. I've seen way too many good hearted people being used as a doormat by the beggars, liars,leeches etc. Sometimes you can't protect them from themselves.