The group trains so that everyone can pair with any other team member and use their powerful Unison attacks. But Shirabe is having trouble pairing up with anybody but Kirika, because of her inability to trust others.
For some reason my heart 
refuses to synchronize
لسببٍ ما يرفض قلبي أن يتزامن
Aus irgendeinem Grund möchte
mein Herz nicht synchronisieren.
Por alguna razón,
mi corazón rechaza el sincronizarse.
Por alguna razón,
mi corazón rechaza el sincronizarse.
Non so perché, il mio cuore
si rifiuta di sincronizzarsi
Não sei por que meu coração
recusa a sincronia
Отчего-то сердце
не хочет синхронизироваться,