Rosabel is one of the only "combination" names I actually like. It sounds like a name by itself, and not like two names smashed together ("Kaylee," "Marianne," etc.).Given the surge in popularity of Isabella / Isabelle / etc. in the Anglophone world, I'm quite surprised Rosabel / Rosabelle hasn't cracked the Top 1000 by now.
My great grandmother's name was spelled "Rosa Bell" with the "Bell" as a middle name that sometimes used with "Rosa". It think it's a pretty, classic combination. It rolls off the tongue.