When it comes to daily life, transparency may be the easiest and most genuine way to build trust. If you have nothing to hide, others will take comfort in believing you and run out of good reasons to hide things from you.
Throughout my entire management career, I have struggled with shielding information from my team to keep the machine running. Secrets don’t make friends, especially in business. As a common example, most managers pad deadlines so that their final deliveries can be met. In many cases, the real deadlines surface and proactive fake deadlines lose credibility. Why not admit final deadlines up front and set padded expectations for your team? Most people understand the truth and will respect you for being honest with them. They will deliver accordingly. Trust me.
Sometimes you need to keep secrets. If that is the case, at least be honest about the reason why (a security clearance or NDA contract are perfectly viable excuses). As hard as it may be for some people to accept, the honest explanation goes a long way. Don’t hide, don’t ignore, don’t dodge the question. Be as honest as you can when you can.