You have several choices to spell Sadie, including Sade, Sadia, Sadye, Sadee and Zadie.
Sadie has several variant forms: Sada, Sadah, Sadelle, Saida, Saidee, Saidey, Saidie, Saydie, Sydell, Sydella and Sydelle.
Sadie \s(a)-die\ as a girl's name. Diminutive of Sarah (Hebrew) "princess", it was used as an independent name at the beginning of the 20th century. It is a very popular first name for women but an unusual last name.
The royal baby has a name! The new little Prince of Cambridge will go by the names George Alexander Louis. For now, he will be known as Prince George of Cambridge.