There’s actually a character named Joscelin Verreuil in the series I’m reading - but he’s male, and a knight. 
I’ve therefore developed a soft spot for it as a,boys’ name, unlikely as it seems. Regardless, I love it. Definitely worth consideration. I’d certainly rather meet a,[name_f]Jocelyn[/name_f] of any spelling than one more [name_f]Olivia[/name_f] or [name_f]Alivia[/name_f].
For what it’s worth, I use the three syllable pronunciation.