When we say a person has HEART, it doesn't mean they are weak and sentimental. We mean they are willing to be exposed, willing to be touched nakedly by the world. They are strong enough not to wear a suit of armor. They are not afraid of their own experience. In this sense heart is the one hundred percentness of experience. It is a strength and fullness in you that come from putting your awareness in the actual experience you are experiencing. This is true even of negative experiences. With a strong heart you are able to be gentle and sympathetic to all your experiences, not only the pleasant ones.

Cynthia Kneen in Awake Mind, Open Heart