Rose was introduced in the season nine finale "Mi Familia" in 2005 as Simon's current girlfriend. The two weren't necessarily serious but she seemed eager to to engage and marry, pressuring Simon into proposing. When at first he refused she took it as disinterest in her and backed away, provoking him to commit to marrying her. By season 10 they were engaged and she was making wedding plans. The initial plan was for the two to engage at the end of their current school year and wed at the end of the following year, but she pressured him into moving the engagement date forward.
During Rose's time on the show, she became a very disliked person by all except for Sandy Jameson, who was her one friend there. Rose was known for being selfish, rude, inconsiderate, and thoughtless, rubbing Eric and Annie the wrong way more than anyone.
By 2006, Simon and Rose changed plans to marry in May, something they both wanted to be ready for but still held insecurities and doubts. Annie, however, had decided that they could not marry, and when an ex-boyfriend of Rose's surfaced in March, she saw an opportunity. Though most had come to accept Simon dating Rose, no one knew her at all, and it was this boyfriend who convinced Rose that she wasn't being a good person. In the April 2006 episode 'Invitation to Disaster,' she had a sit-down confession with Annie, explaining that she had been unaware of how she was acting and that her relationship with her parents and never really being disciplined or close to them at all was part of the reason. This provoked Annie to see her in a different light, and while she and Annie took on a mother/daughter relationship, no one else was crazy about them marrying. It was her ex-boyfriend Umberto who made her realize she wasn't ready to marry and that he still had feelings for her. So although they had gotten to the wedding day, they ended up parting ways amicably. It is unknown whether they still keep in touch---Simon has not recently been to see the family and neither has Rose.