Actress Samantha Ruth Prabhu, who has blockbusters such as "Theri", "A...Aa" and "Janatha Garage" to her credit this year, rues that there are no meaningful roles for a southern heroine and that it's very disheartening."Realising just how hard it is to get a meaningful role for a heroine in the south," Samantha wrote on her Twitter page on Saturday.With five major releases this year so far, Samantha could have signed films left, right and centre. However, she has signed only one yet-untitled Tamil film."I haven't signed as many films as I'd like to because there are no good roles. As disheartening as it is to say," she wrote.Having walked out of Dhanush's Tamil gangster drama "Vada Chennai" last month, Samantha has a project with Sivakarthikeyan next.