Dazai sends Akutagawa on some errands, but despite his best efforts, he doesn’t seem to have what it takes to go shopping.
My ability acted 
up on its own
تصرّفت قدري
من تلقاء نفسها
Hat meine Fähigkeit von selbst gemacht
Mi poder salió solo
C’est parti tout seul.
La mia abilità agisce
per conto suo
Minha habilidade agiu por conta.
Само собой
получилось.