Marta Balaga Joachim Trier’s “The Worst Person in the World,” about a young woman figuring out life and love, might have brought Renate Reinsve the best actress award at Cannes, but the two actually started their collaboration in 2011 on “Oslo, August 31st” – Reinsve’s very first film. “I was an extra with one line,” she said during an online discussion with the director, accompanying a surprise screening of their film at Rotterdam Film Festival. “The Worst Person in the World” was recently shortlisted for Best International Feature Film at the Academy Awards.