Talking about stealing is especially difficult. Take the following four steps and everything should fall into place.
1. Prepare -- Make some notes about the situation and your feelings. Write about where you are, where you want to be, and how you might get there.
2. Set the stage -- Sit down at a time when you are both clear headed and able to give this important conversation the time and energy it deserves.
3. Speak from the heart -- Do not point fingers of blame or suspicion. Instead focus on yourself and what you need. Make it clear that this is about something you need to say and not something the employee has done.
4. Listen, listen, listen. Listen to what your employees have to say. Listen as if you are an outside observer -- without judgments.