How do we build trust between humans and AI?

When she calls me, she can immediately tell if something is wrong, simply from the way I say "Hello" or "I'm fine". Like many relationships with those we hold close, my mom and I have built a level of trust to the point that she knows how I'm feeling from a simple word or phrase. But unfortunately, I, like many others in the world today, spend as much (if not more) time interacting with technology as I do with the people close to me. Yet unlike talking to my mom or a friend, the way we interact with devices is completely transactional. My cell phone can't read between the lines and understand what's really going on with me.