Isaku is frustrated with Keiya when he doesn't even try to pass his tests at school. They agree that she'll give him a reward if he passes his next make-up exam, but the reward he asks for is nothing Isaku could have expected.
...he's fired up all of a sudden.
.لقد تحمس فجأة
Auf einmal war er hochmotiviert.
-Se motivó de golpe.
-De nuevo se agotó…
Se vino arriba de repente.
Il est motivé à fond, en fait.
... per qualche motivo 
è diventato super motivato.
Ele está todo empenhado
por algum motivo.
Смотри-ка, как загорелся.