I would say Deva comes from the Slavic "deva"
*with a terrible exagerated accent* which is mean "young girl", so there you go! *end of terrible exagerated accent*
But seriously, "deva" is an old Slavic word for a girl. Today, it's preserved in the Russian "devochka", the Serbian "devojka", the Bulgarian "devoyka" (all meaning "a girl").
Deva also doubles for "a virgin" and brings connotations to Deva
Maria (Virgin
Mary) - in that sense, it is somewhat like
Virginia. It is a really old name and I didn't know it is still used, although I know of several little Devina's (an elaborated form of the name).
I hope that helps