"Happiness" can be used in many different contexts to describe a wide range of feelings and situations. Here are some examples of how "happiness" can be used in sentences:
Marina was a confident, happy child.
I'm just happy to be back running.
Except for her illnesses, she had had a particularly happy childhood.
It had always been a happy place.
If you are not happy about a repair, go back and complain.
He's happy that I deal with it myself.
I'll be happy to answer any questions if there are any.
That's a risk I'm happy to take.
Happy Birthday!
Happy Easter!
By happy coincidence, Robert met Richard and Julia and discovered they were experiencing similar problems.
These sentences demonstrate the versatility of "happiness" and how it can be used to express a range of emotions and situations, from personal contentment to unexpected good fortune.