Expressing Doubt: In Spanish, we use specific interrogative structures to convey skepticism, surprise, or genuine uncertainty.

Register: Phrases like “¿Seguro?” are informal. For formal situations, use “¿Está usted seguro/a?”.

Gender/Agreement: Many expressions involve adjectives (e.g., seguro/a, convencido/a). You must match the adjective to the gender of the person you are talking to.

Nuance: “¿En serio?” and “¿De verdad?” express incredulity, while “No estoy convencido” shows a more logical hesitation.