Rosalina is a character who debuted in the American Idol reboot, but she wasn't properly introduced until Mario's New Girlfriend! She is Mario's girlfriend. She is a human that was born and raised in space by two green aliens. Although she is from Outer Space, she is ranked as #1 on Beautiful/Sexy on the List of character attribute rankings.
In Rosalina's Parents!, it is revealed that Rosalina was found as a baby by two green aliens, who adopted her, although they didn't tell her that they were not her real parents. Her real parents are unknown.
Rosalina first appeared in the American Idol reboot series, but she wasn't properly introduced until the video, Mario's New Girlfriend!, where she and Mario fell in love and started dating.
There have been times where Mario and her argue, but these arguments mostly have been caused by Jeffy. There were also times when Rosalina was theorized to have broken up with Mario, but they remain together to this day.
In her first two appearances, she was a crybaby who sobbed over the stars because the sun took them away. Rosalina missed her star, Luma. But then, Mario brought him back to her, causing her to love him.
For the rest of her appearances, she has been portrayed as a stereotypical ditzy dumb blonde. Despite this, she is incredibly sweet and caring. She is very kind to Mario and is 100% in love with him, unlike Peach, who treated him like dirt. Rosalina also has deep motherly affections towards Jeffy, while Mario hates Jeffy and wants to get rid of him (completely justifiable). She can get defensive of Jeffy to the point that she ruined her own boyfriend's reputation, claiming to the police that Mario likes to beat Jeffy up all the time, which is not factual.
However, in recent appearances in Modern SML (2016-present), Rosalina is shown to unreasonably impatient towards others, especially Mario, to the point where she acts like a selfish brat, shown in Jeffy's New Toy! (where she imitates Mario being shocked by her sudden appearance in his house). In the same episode, she is revealed to have an evil and torturous side, as she terrifies Mario just for lying to her. This revealed that Rosalina can also be hypocritical, as she criticized Mario for lying, even though Rosalina lied to the police that Mario likes to beat Jeffy all the time. Rosalina often has a tendency to jump to assumptions as well, as she beat Mario up in Jeffy's Cellphone! for apparently calling a prostitute up, without letting him give an explanation. Furthermore, Rosalina was with Mario the whole day, leaving there no time for Mario to call a prostitute. She also attempted to call the police on Mario in The Dead Body!, assuming that Mario purposely killed a hobo, without any evidence that he purposely did so, or letting him give an explanation.
Additionally, Rosalina is shown to be immature for her age, due to her initial cries over the sun blocking the stars, though this seems to subsided. In addition, in Jeffy's Brain!, she thought it was perfectly acceptable to throw her plate of unwanted food at the wall, just because Jeffy, a twelve-year-old kid who also acts immature, does the same multiple times.
Rosalina truly loves Mario and has a strong bond with him. He's Rosalina's boyfriend. She is mostly seen hanging out with him. She also takes care of Jeffy with Mario as a parental guardian. Nowadays, Rosalina rarely gets really irritated with him being mean to Jeffy, though.
After Jeffy got taken away in Jeffy's Parents!, she gets disappointed at Mario for his heartlessness and leaves the house, leaving Mario very lonely, only to fortunately becomes happy when Mario decided to keep Jeffy.
Rosalina is very nice to Jeffy and seems to really care about him. Rosalina loves Jeffy. She does not seem to have a serious problem with Jeffy's unintelligence and is willing to spend time with him. Although she is not Jeffy's birth mother, Rosalina can be seen as a good adoptive mother to him and and will often get defensive to Mario about abusing Jeffy, and intervenes when necessary.
The only time Rosalina gets frustrated with Jeffy was in Jeffy Gets Potty Trained! when she forced him to eat his peas, but Jeffy demanded Marshmallows instead.
Rosalina's ex-boyfriend that Mario got jealous over. D-Money broke up with her since she was being dragged along with him too much. Her parents had preferred her dating him instead of Mario.
Rosalina first met Bowser Junior in Jeffy's Birthday!, when Jeffy was about to go on the jungle gym with Junior and his friends, and Junior found her really hot and liked her breasts.
In Smart Jeffy, Junior caught Rosalina's attention by calling her "Busty Tits" and Junior explaining to her what happened to Jeffy.
Rosalina holds a grudge against her since Jeffy's Parents!. She can't stand her beating up Jeffy. When Jeffy gets taken away, she got frustrated with Mario, yelling that she can't believe he let Nancy Jeffy| take him away, trying to convince him that Nancy beats Jeffy, but Mario shows absolutely no concern, even stating that it's good that she beats him, leading Rosalina to break up with Mario for his heartlessness.
Rosalina has generally been well received by fans. Fans say Rosalina is better than Peach since Peach treated Mario like dirt, but Rosalina treats him better.
But after Jeffy's Bad Word!, thanks to Logan's misguided flanderization, her popularity was severely damaged and caused many fans to really hate her.
Fortunately, after Jeffy's Mistake!, her reception has regained overwhelmingly positive reviews leading her to become the most loved characters ever once again.
However, after Jeffy's New Toy!, Rosalina's character became heavily panned, due to her cruel behavior, scaring the living daylights out of Mario just for lying to her.
Thankfully though, after Jeffy's Piggy Bank!, Rosalina's positive reception returned, due to her kind act of selling $500 worth of things in order to prevent Mario from getting pushed into a woodchipper.
However, although Rosalina had once again become a well-received character, many fans still hated her, due to not being able to forgive her for the events of Jeffy's Bad Word!, Jeffy's New Toy!, and other times that she exposed her cruel-spirited nature towards Mario.
Yet again, however, Rosalina's reception declined, due to Rosalina acting like a cruel jerk to Mario and flirting with Jeffy just because of his French accent in Jeffy's Brain!.
Youtuber Kushowa says Rosalina is one his favorite characters and finds her "pretty funny!" And he also stands up for Rosalina in bad situations when Mario gets frustrated at her or at Jeffy.
Draco Lumina says that Rosalina is the worst SML characters ever to exist, he really hated how abusive she was to Mario and a Crummy SML Character video on her.
Although Rosalina is typically portrayed as kind-hearted, she is shown to have an evil and torturous side in Jeffy's New Toy!, where she terrifies Mario by dressing up like a disturbing-looking doll just for lying to her.