Trust is a funny concept which I've learned several things about from my adventures. It started when I went surfing and had a rental board. Believe it or not, you begin to establish a relationship with this inanimate object. It takes a bit of time, but you learn its boundaries. You learn what you have to do to get the best back from it, and then you learn to trust it. You begin to have faith that as soon as that tail goes up on a wave much bigger than you thought you'd have the balls to go after, it'll stay afloat and glide down the almost intimidating drop you're facing. And then it does. You've managed to stand up and now you're on a joyride of adrenaline together.
Then, while on horseback in the Colombian mountains, I was faced with the same issue. Here I was having to trust this horse I just met. That it will make it down the steep hills without tripping, rolling over, and crushing me under its massive (but adorable) weight. Then slowly you figure out how to work together, how I should lean in the saddle to ease the journey for her, how to encourage her, and her boundaries. And before you know it, we've become a team, working together and exploring the countryside.
So I've come to the following conclusion: Trust is a universal phenomenon that comes slowly and starts with us getting outside of ourselves. No matter if surfboard, snowboard, horse, or partner. Whatever you're riding (ha ha ;P) be sure to give it time, pay attention to what is needed from you, and most importantly take a leap of faith. More often than not, they want to carry you and enjoy that ride with you.