No, "Valentino" is not an Italian slang equivalent of "Valentine."
Specifically, the Italian word is a long-established masculine first name among Italian language speakers. The pronunciation is "VAH-lehn-TEE-noh." Many Italian names have masculine and feminine equivalents. The feminine equivalent, "Valentina," is pronounced "VAH-lehn-TEE-nah."
"Valentine's Day" in English is Festa di San Valentino in Italian.
In italian it means strong and in french it means valentine.
"Happy Valentine's Day!" in English means Buon San Valentino! or Felice San Valentino! in English.
Buon San Valentino in anticipo
"Happy Saint Valentine's Day!" in English means Buon San Valentino! in English.
"Buon Saint Valentine's Day, love! I love you!" is a mixed Italian and English equivalent of the mixed English and Italian phrase "Happy San Valentino, amore! Ti amo!" The masculine singular adjective buon and the masculine singular phrase San Valentino translate literally as "good" and "Saint Valentine" in English. The pronunciation will be "bwon san VA-len-TEE-no a-MO-rey tee A-mo" in Italian.
There is no saint named Valentino but there are several named Valentinus or Valentine in English.
Felice San Valentino, Sexy! and Auguri di (or per) San Valentino, Sensuale! or Buon San Valentino, Sensuale! respectively are Italian-American and Italian equivalents of the English phrase "Happy Valentine's, Sexy!" The above-mentioned examples respectively translate literally into English as "Happy Saint Valentine, Sexy!" for Italian-Americans and ""Greetings of (or for) Saint Valentine, Sexy (sensual, sensuous)!" and "Good Saint Valentine, Sexy!" for Italians. The respective pronunciations will be "fey-LEE-tchey san VA-len-TEE-no SEK-see" in Italian-American and "ow-GOO-ree dee (or per) san VA-len-TEE-no sen-SWA-ley" and "bwon san VA-len-TEE-no sen-SWA-ley" in Italian.
Valentinus is the Latin for Valentine, as in St. Valentine.
Down to Earth - 1984 A Valentine for Valentino 2-13 was released on: USA: February 1985
San Valentino
In Italian it translates to innamorato. Always remember that depending on the context of your sentences, the translation can vary. There may also be slang terminology if you were to travel to Italy. Keep in mind that online translators may not always be correct, they are a reflection of the exact words you have typed in.