Be kind, be open to trusting people but don’t become anyone’s doormat! Some people will take advantage of another’s kindness and time. If you don’t put a stop to that kind of abusive behaviour (I call shit what it is & don’t sugarcoat), do not expect anyone else to stop it for you.
Personal boundaries are just that - personal and that means you establish your own boundaries in regards to how you want to be treated. For personal boundaries to work, one must be committed to being firm about maintaining them - especially if you are someone who is prone to being weak when others try to guilt trip you. Stand up for yourself. You have that power. Own it. And learn how to completely let go of those who are treating you like a doormat instead of a valuable person!