Gustave has taken it upon himself to observe Marion and Sanglain following the death of the Princess and DT.   But KT thinks Gustave is in the city of Marquesas for other reasons. 
Do you honestly need to 
think about the reason?!
¡¿Honestamente necesitas 
pensar en la razón?!
¡¿De verdad necesitas pensar cuál es el motivo?!
Precisa mesmo pensar no motivo?!