Trust is usually easiest to acknowledge at the beginning of a relationship. Perhaps because your partner has not let you down yet or maybe you tend to be a trusting person. However, the reality is that there is no basis for trust until your partner has let you down or you have questioned your trust in the relationship. As crazy as it sounds, trust is built slowly in your relationship over time and what can help build it strongly is in part due to the misunderstandings or even betrayals that you experience. Betrayals can be small or large, so it may test your trust slowly or all at once. Either way, it is an opportunity for trust building. Let's take a look how this can help strengthen your trust.
The Gottman Institute (which has done years of research on relationships) has gotten it down to a science. Building trust in a relationship takes attunement. It's actually small moments of attunement and repairing the moments of disappointment/hurt that strengthens your trust. To "ATTUNE" to your partner means being Aware of his/her feelings, Turning towards his/her feelings, being able to Tolerate differences in viewpoints, Understanding your partner, responding Non-defensively, and responding with Empathy. Any of these things can be accomplished through intimate conversations and small moments of acknowledgement throughout your relationship. For example, let's say your partner was going through a career transition. It's been tough for your relationship (financially and emotionally). So one day when your partner vents about having a hard time finding a job or frustration in his/her transition, you could either shoot back with "that's nothing compared to what I had to deal with today" or you could "ATTUNE" to his/her emotions by saying "it's tough on you, but you're trying your best here". Wow, what a strong message of "you can trust me with your feelings" for your partner to hear.
So how does attunement work to fix trust after a betrayal? Attuning to your partner throughout your relationship will help when dealing with betrayals because you need to "ATTUNE" to one another's emotions in order to engage in conversation and repair the relationship. Also if you've been attuning to each other before the betrayal then you'll have a stronger sense of trust to work with after the betrayal. The reality is that you can't build trust on a conditional basis that you will only trust until there is a betrayal. Working through a betrayal can be a strong affirmation of trust and can increase the intimacy in your relationship. In contrast, your inability to rebuild trust after a betrayal is actually not due to the betrayal itself, but it's actually due to the Un-Attunement towards your partner and the belief that you can do better. This is what contributes to distrust and erosion of your relationship.
If your relationship were a house, trust is the frame. As discussed in the past, having a strong foundation is very essential to your relationship, but a house with a weak frame will blow right over as well. So ask yourself again, how did you come to trust your partner? Maybe your trust is strong now, but what will it withstand?