"We're never so vulnerable than when we trust someone - but paradoxically, if we cannot trust, neither can we find love or joy." Walter Anderson
Trusting is placing confidence in someone even though there is a risk that it won't go well. If there isn't a risk of failure, I don't think it's trust. Everything a leader does in business has some element of risk, so requires trust. It's accepting the risk that the person may not be ready and trusting anyway that makes a great leader. Protecting your team from stretching beyond their comfort is a disservice to the employee.
I was confronted by Joel writing that interrupting is a sign of mistrust. I am terrible about interrupting and it is an ongoing project for me. With so much virtual communication (webinars, conference calls, etc.), I'm always talking over people.
In the book, Joel uses RACI as an example of being clear about roles which will make trust easier. If you're not familiar with this, it's a process that can be used to identify governance (who makes what decisions) and who contributes to the discussion. This can be a useful team process and for some aspects of project work. Here's a link that explains more.
One of the most difficult things a leader has to do is allow others to make the decisions they are responsible for. Has this happened to you? A member of your team comes in to ask your opinion about a problem they are having. You respond by telling them what to do. The team member leaves knowing now that you will always tell them what to do if they ask, and likely, you'd like them to do that. If, instead, you ask them to share two different ideas they have for how to solve the problem, and then which they prefer, you are teaching them to be leaders. It is very difficult for me not to immediately come up with a solution, most notably when I'm the busiest.
Finally, when you find out about a decision that one of your team members has made that you would not have chosen, take a deep breath and think about whether it really makes enough difference to degrade their trust in you by overturning it.