When we become parents ourselves, we are giving our children a platform for trusting others. Are we calm, reasonable, warm, available, and supportive? It means a great deal to have a parent who can be counted on. Children need parents who are predictable, present, involved, and providing meals, love, and attention. When parents are unpredictable, absent, hostile and volatile, it blows apart the empathic envelope of trust that parents should have around their growing children. For our children to trust us, we must be trustworthy as parents.
As a teen or an adult, it takes courage to let your guard down and be vulnerable with significant others ---to trust a few people to be there for you, to support you, and not to betray that trust. Some people have difficulty trusting others because they know that they can't be trustworthy themselves.
Trust is built over time, like depositing coins in a bank, or marbles in a jar. Every repeated experience where your trust is maintained, and the loved one is a person of their word, helps to keep that bank account balance up or that jar filled. If trust is broken, it is a much harder thing to rebuild later. Sometimes trust can't be rebuilt at all.
How is trust built or maintained at a high level?
Teens, in particular, tell me they shut down when they share something personal with a parent, and the parent shares that sacred trust with others.
I like to think of it this way: in order to establish the feeling of safety with another person, you must be able to trust them. To build feelings of intimacy, you have to feel safe. These are the building blocks of close and caring relationships, whether between partners, between parent and child, or close friends. Safety, trust, openness, intimacy, and vulnerability are best when they travel as a team. A relationship can only be as strong and as deep as your commitment to these hallmarks of conscious relationships, and the similar commitment of the other person you are in relationship with.
So there are two parts to trust: being a trustworthy person yourself, and choosing intimate others who are deserving of your trust, and can give you that gift in return.