Joy.

Joy -
–noun 1. the emotion of great delight or happiness caused by something exceptionally good or satisfying; keen pleasure; elation: She felt the joy of seeing her son's success.
2. a source or cause of keen pleasure or delight; something or someone greatly valued or appreciated: Her prose style is a pure joy.
3. the expression or display of glad feeling; festive gaiety.
4. a state of happiness or felicity.
–verb (used without object) 5. to feel joy; be glad; rejoice.