HannahI am so deeply sorry for the loss of that childyour lossyou lost her, too. Acknowledge the loss.The kindest thing you can do is simply say 'I am so very sorry for your loss.' or 'Please accept my most sincere condolences on your loss.' Keep the letter as brief and as short as possible. Be sincere and express your feelings of sympathy. Examples of what to write in a sympathy card include: The loss of a child is a pain that no words or actions can heal.