Froh

The word froh means contentment, often used in a context of contentment-being relieved or temporary joy. Some examples:

Peter ist froh, dass er die Prüfung bestanden hat.

Peter is happy that he passed his exam

 

Sabine ist froh , dass sie rechtzeitig den Bus erreicht hat.

Sabine is happy to have reached the bus.

 

Glücklich

The word glücklich can be translated as happy, unlike the word froh, with “glücklich” are associated deeper emotions.

 

Michaela ist glücklich, weil sie ein neues Auto hat

Michaela is happy because she has a new car.

 

Die Mutter ist glücklich, denn ihr Sohn hat eine gute Note in Mathe

The mother is happy, because her son has a good grade in Mathe

 

Zufrieden

Zufrieden can be translated as being happy with something or someone. Some examples:

Peter ist zufrieden mit seinem Leben

Peter is happy with his life

 

Der Vater ist zufrieden mit seinem Gehalt

The father is happy with his salary

 

In short, one can say that the words zufrieden and glücklich have a certain similarity, but with glücklich the emotions are deeper as with zufrieden.

The picture on the cover reflects very well the state of “glücklich sein” this couple seems to be very happy.

In the following link you can read more about grammar and the different meanings of words:

Difference between suchen and finden