It's just a bit much. I also think all of the -ella and -bella names will go out of style soon. It fits right in with
Isabella,
Annabelle etc. and seems a bit bland and boring.
Rosabel is better, Rosabelle is too sickly sweet. All of them seem too fancy and sweet next to
Nathaniel,
Sophia,
Juliana and
Dominick which all seem more down to earth. I think I'd go with
Rose or maybe
Rosalind.
If you stick with
Rosabella then it needs a simple middle name that isn't too sweet.
Rosabella Lily is way too much and doesn't flow well. The other two seem too long.