Sympathy expression or feeling of pity and sorrow, when we know someone or people are unlucky or have trouble and in bad condition. We express it directly to him/her orally  or we can use a letter or card by post also by short message service (SMS)

Example :
•    Ow, how awful!
•    How pity you are!
•    Oh, dear.
•    I know how it feels.
•    Oh, no!