The name Roberta is a girl's name of English origin meaning "bright fame". Roberta and is often added to lists like Feminizations and discussed in our forums with posts like "totally, kinda or no way with middles".
From the experts:
Roberta has been one of the most successful feminization names, up at #64 in 1936. It's a name that's found all over children's lit, often nicknamed Bobbie or Robbie, though Bertie is another possibility. Notable bearers have included singers Roberta Flack and Roberta Peters--plus it's the birth name of Joni Mitchell.