I agree with KBMK. We teach people how to trust us, how to interact with us, based on what our own interpersonal boundaries are. If you are a pushover, people will NEVER respect you and will always let you down because you can't count on someone who doesn't respect you. If you have strict boundaries and people know what your boundaries are, you have more chance of earning people's respect and trust of you, b/c you show them that you cannot be taken advantage of without them experiencing consequences as a result of breaking your trust.

People don't just act trustworthy with you. You have to set up the parameters with them by telling them what your boundaries are. So, its about communication skills with other people and being consistent.