Express your heartfelt sympathies. Some example messages would be, please know I am thinking of you during this painful time.Here is my suggestion on what to write in a sympathy card or message to your boss: "Please accept my condolences on the death of your ____. Be sincere and express your feelings of sympathy. I was sorry to hear of your recent bereavement. Writing a condolence message is an emotional task. Here's tips and examples of how to sign a sympathy card for coworkers, friends, and more. I simply say I'm so sorry to hear of their loss. I often add that I'm always here if they need someone to talk to.