Hi and welcome!
I think this is an excellent question and something often overlooked. Trust isn't automatic or immediate.
In fact, I deeply distrust people who trust too quick.
The Only way I know to build trust is by taking time and learning the other person. Slowly learning that the persons words and actions match.
I also believe that trust can only grow when both partners consistently show trustworthy behaviour.
Over time...with open and honest communication, you will notice trust blossoming.