I can't speak for all INFJs, but for me, trust comes form respect and a tried-understanding.
An INFJs awkwardness is mostly fear. Because of the fear of rejection an INFJ won't reach out to you unless you reach out first.
Let the INFJ into your thoughts, past, feelings, problems, issues, etc. first without expecting the same back. We're not the most willing to express ourselves full-on without knowing who we're confiding in. If they feel that connection of ‘need’ with you, they’ll grow more comfortable.
When they do confide something with you, try your best to understand. Even if you can’t fathom how they feel or why they think a certain way, learn. As long as we see a true effort and interest to understand, we’ll accept your compassion and friendship. We don’t expect to be figured out. We don’t want to be figured out. We just want respect and attentiveness. Be open to our ideas, interpretations etc. If we see that you’re listening, we’ll want to be heard more often.
Now here’s where things tend to go wrong. Once an INFJ opens him/herself to you, don’t disregard how major that is for them, even 10+ years into the relationship. If they tell you something and you reject it or ridicule it, even if nonchalantly, they INFJ will back off for awhile until they can process where you’re coming from with the comment.
For me, my initial feeling when I don’t feel accepted or heard is anger and frustration, but once I think it over, I can forgive the person and understand where they’re coming from. But I do need time.
It’s in this time where I’ve found that most people lose my trust. Instead of accepting that I don’t want to share my feelings with them for the moment, they push and push and push until I lose respect for them.
Once I feel betrayed, I can never gain back the same openness with that person. Ever.
Understand, though, that it takes a lot for that willingness to share a mutual counsel to break down completely.
INFJs are, after all, an understanding group of people. We realize that emotions often take precedence in conversation, comments, actions, and we are willing to forgive and move forward. Yes, that conflict will always be in the back of our minds, but the relationship we’ve built with the person who hurt us will remain intact until we’ feel we’re forced to end it, or else end up being hurt far worse.
If you hurt an INFJ, first try and explain yourself, second give them space to think it over, and if the person still doesn’t come around, apologize once more, than let it go. I know I can’t stand when a person isn’t able to let go. I feel like they depend too much on me and I become afraid that I’ll only let them down. By making your status known to them, (hey, I made a mistake, I’m sorry I hurt you. I’d really like to continue being friends but I understand that you need some time right now…), feeling sincerely apologetic, and respecting that reserved part of them, they’ll come around, I can almost guarantee it.
As far as earning the trust, my best advice would be to be real. Don’t hide the parts of yourself that you think most people won’t accept. I can always accept a person, no matter what, truly. If you have a problem, let us in. We don’t like feeling excluded, especially from someone we care apart. We don’t like artificiality in our relationships.
Embrace our need to help. But don't be afraid to tell us to back off. If you feel like in the past INFJs have tried too forcefully to 'save' you, let them know that you're comfortable where you are and don't really want them to force you into something or someone you're not. If you present your need in a way that doesn't come off as threatening, and maybe even relate it to a way that, that person has felt in the past, we won't be upset by it.
Again, all INFJs are different, but this is how I feel about trust and relationships. :]
