Mavis is headstrong, intelligent, curious, dramatic, independent, and beautiful. She has a little bit of an attitude, but she is very sincere and gentle. An innocent, wholesome, soft spoken and, lovable person. Mavis wants a little bit of independence and trust from her father and often gets bored. She dreams of exploring the world and experiencing all the sights and sounds that the world has to offer, but all that becomes an reality when she meets Jonathan and unknowingly, falls in love with a human.
She is also, always willing to help someone out, even if her own life is in danger. Proof of that is when she was at the "human" village. After all the threats the pitchfork-armed, torch-wielding "humans" made of burning her clothes, taking her candy, biting her toes and even shoving garlic bread in her face, she still offered her help when the "humans" were on fire. She said "Holy rabies! You're on fire. Can I do anything? Can I help you?"
In the second film, after becoming a mother Mavis begins to adopt some of her father's overprotectiveness and attachment to her child, going so far as to baby-proof everything in the hotel, rarely leaving his side and wanting to move to California in order for her son to grow up in a safe environment and around other children like him. Unlike her father she doesn't seem to care that Dennis isn't a full vampire and accepts him for who he is.... even standing up to people who she assumes are prejudicing him for being a hybrid.