Possibly the name is related to Siddel, a male Old English meaning "from the wide valley". Unless the character in the book is into Hindu mysticism (Sidda is a school of Yoga meditation).
Lemme thow in some female names related to destiny:
*
Moira , meaning fate (Greek). (Note to
Mike C - please make a note of this, because in your list the name appears as an "anglicized form of
Maire")
*Eutychia, means good luck (Greek). Sounds beautiful in Greek but is understandably cumbersom in English!)
*
Felicia, female form of
Felix, meaning luck (Latin)
*
Zelda, meaning luck (Yiddish)