Sii felice! is an Italian equivalent of the English phrase "Be happy!"
Specifically, the present imperative sii means "(informal singular you) be!" The feminine/masculine adjective felice translates as "happy." The pronunciation will be "see fey-LEE-tchey" in Italian.
"Be happy!" in English is Essere felice! in Italian.
"I am happy!" in English is Sono felice! in Italian.
"You are happy!" in English is Tu sei felice! in Italian.
"I am happy with you!" in English is Sono felice con te!in Italian.
"Happy home!" in English is Casa felice! in Italian.
Infelice
"Happy birthday, auntie!" in English is Buon compleanno, zietta! in Italian.
"I'm happy for you" in English means Sono felice per tein Italian.
Così felice! in Italian is "So happy! in English.
Buona vita
Sei felice con me?
"Happy 80th birthday!" in English is Auguri di buon ottantesimo compleanno! in Italian.
"I am very happy that you wrote to me" in English is Sono molto felice che mi scrivesti in Italian.