Kindness

Kindness is a potential quality of an act in which one person or entity somehow gives freely something of value (abstract or tangible to another) to another, when this other needs this at a certain time.

To qualify this further, kindness in certain circumstances could be seen as acting pro-socially towards someone who you might not normally act pro-socially towards.

Of course, a person could be kind to a person they know well. Perhaps a pair of people are kind to one another, and treat each other tenderly and with affection.