These are the tales of a certain couple who climbed a mountain... a college student who moved into a certain apartment building... and  a certain pair of siblings...
Wait, are you being serious?
مهلًا، هل أنت جاد؟
Was? Ist das dein Ernst?
¿Qué? ¿Es en serio?
¿Qué? ¿En serio?
Quoi ? Tu le penses ?
Espera, está falando sério?