Love is both an action and a feeling. The action of love generates a blissful feeling called by the same name. When the action stops, the blissful feeling is replaced with pain. There is a similar feeling called lust which may be confused with love. You need to decipher between the two in order to have a healthy heart. Every person is capable of great love (and its opposite, fear, which generates all painful emotions such as hate, greed and jealousy).