Hi! I hope that my answer helps you understand more.
In these cases you have to dispel fears that an employee has. You don't want the employee feeling as if they cannot be open about any situation. You can encourage them by showing respect. They will feel if they have respect from an employer that things will be fair whatever the situation may be. You can always encourage with your words. Be kind and remind them that they can come to you as their supervisor. Let them know that policies and guidelines apply to ALL workers, including those who are higher in authority. Employees do have to feel that they won't be looked down upon for doing the right thing. Let them know that when they do come to you it will be confidential. These steps will provide a bond of trust between supervisor/manger and employee.
Please let me know if you need any clarification. I'm always happy to answer your questions.