While frail in appearance, Maria was strong in spirit. Eternally cheerful, optimistic and positive despite her condition, Maria could see the good in almost anyone or anything. She was likewise a very kind, caring and thoughtful soul who always put others before herself, supported her friends, and held an unconditional love for the people of the world, even showing compassion towards her enemies when they were distressed. Because she never got down to earth, Maria was very interested in the planet and wished to see it.[1] She was as well very encouraging as she could make others accept themselves and calm others down when in stressful situations, including Shadow.

Always thinking about others before herself, Maria was one who found it easier than most to forgive and forget, not to mention trust. Even after GUN violently raided the ARK and shot her down, Maria did not hold any ill will against the people on earth and only wished for them to live happy lives. She was also was utterly selfless as she sacrificed her life for Shadow's sake, having faith he would carry on her dreams for her.

Despite her youth and frailness, Maria was brave, determined, and had a strong sense of righteousness. When the Artificial Chaos were on a rampage, Maria wanted to stop them to save the innocent, and during the GUN's raid on the ARK she refused to leave the injured researchers behind. Even on her deathbed, Maria remained undeterred and only wished for Shadow to fulfill his purpose.

I'll leave it up to you to determine what voice best fits Maria, however remember she's a 12 year old girl and has a terminal illness