It's hard to open up our hearts and trust when we have been hurt. Many things keep us from trusting, like fear and rejection and pain we've incurred in the past when we have been vulnerable with others. The depth of our relationships is inversely proportionate to the level of trust that exists. When it's there in spades and it hasn't been broken, the relationship is mutually satisfying and generally safe for both people inside of it.
Because we are all damaged, most of our relationships bend and break at some point, and then trust has to be rebuilt. With God this principle is also true. Our perception is what determines our reality, and when we perceive that God has let us down or hurt us, we are often slow to trust him again. I don't think God is as concerned by this process as we are. He doesn't move away from us, but we move away from him, sometimes when life is hard and also when it's good and we feel we don't need his peace and love and grace.
Trust is an important factor within ourselves. When our confidence is low, we don't believe in ourselves, and don't move forward in our actions. Baby steps are good in this situation, as a way to prove to ourselves that we can do what we are afraid that we can't do. When we master something small, again and again, eventually we build confidence to try for the bigger things, and our trust in ourselves slowly grows and becomes something we can rely on.
So much of life is fragile, and trust is at the top of the list. It can be built up over years and years, and broken in a single moment, and then it takes time to bank it up again. When the trust is damaged between people, each person must do their part to see it grow and blossom. One person can't traverse the entire distance and do all of the work. That's not a healthy model for any relationship, and I know, because I've tried and it doesn't work. You can only own your part, and the other person must do a similar amount of work, or the relationship will be hopelessly lopsided.
Sometimes you can't make it work, no matter how hard you try, and then you have to step back and hope that in time it might be different. There are no guarantees with something as tender and unpredictable as human relationships. Even within ourselves, we can't foresee the kind of opposition we might face, and if we will be strong enough to withstand the forces that can come against us. And we see God through our own damaged eyesight, not as he really is, so our relationship with him is flawed and has the potential to change at any time.
As we become healthier within ourselves, everything becomes different. We change, and our circumstances (or our reaction to them) also change. With every inch of ground we gain in our confidence, our ability to trust in a healthy way also grows, and we can see where we are safe and where we should draw a boundary line and wait to proceed.
There are no hard and fast answers when it comes to trust. Our intuition is important, as are flags from our past wounds and fears which warn us against repeating past hurts. We have to feel our way, and do the best we can to offer our trust where it's being reciprocated, and guard ourselves when we need to be cautious.