Gender: Feminine
Origin: Greek
Meaning: “Daughter of Ares.”
Pronunciation: (sih-NOH-pee)
Nicknames: Sini, Sope, Pepper, Poppy
Detail: A natural satellite of the planet Jupiter.
Sinope is the name of five different rivers in Greece and Turkey and in Greek mythology the goddess of those rivers.
The Character of Names 
This is a beautiful name. Sinni would make a cure nickname.
I agree, beautiful name, would make a great alternative to Penelope.