The meaning of the verb "sich freuen" depends upon the preposition with which it is used. If the verb is followed by "auf" and the accusative case, it means "to look forward to". But if "sich freuen" is followed by "über" and the accusative case, then it means "to be happy about":
Grammar 25: Prepositions after "sich freuen"
"auf" + Accusative
Meine Kinder freuen sich schon auf das Wochenende.
("My children are already looking forward to the weekend.")
Ich freue mich auf eine schnelle Nachricht von euch.
("I look forward to a prompt response from you.")
"über" + Accusative
Ich freue mich über eine E-Mail oder einen Anruf!
("I'll be pleased to receive any e-mails or phone-calls.")
Jutta freut sich über das Geschenk.
("Jutta is pleased about the present.")
Note that "hoffen" the German verb meaning "to hope for something" also takes "auf" and the accusative case as this verb too implies "looking forward to something":
Ich hoffe auf baldige Antwort von Ihnen.
(I look forward to receiving a prompt response from you.)
Sie hoffen auf eine schöne Zukunft.
(We hope for a good future.)
