Heartfelt thanks is just that...thanks felt from your heart. Tell the person exactly why you are thanking them, and what their act of kindness meant to you!
People want sincere thank you's. Nothing worse then phony thanks. Look at cards and see that they say, you can see this and use your own words to express how you feel. You can always make a special dessert for them.
Be genuine. Say what you are thinking - even something like 'I don't know how I can possibly express how grateful I am' can work quite well if that is the case.
