Expressing Doubt and Uncertainty

Phrases for expressing doubt, uncertainty, possibility, and speculation in Spanish.

Expressing Doubt

Dudo que... (I doubt that... + subjunctive) No creo que... (I don't think that... + subjunctive) No estoy seguro/a de que... (I'm not sure that... + subjunctive) Es dudoso que... (It's doubtful that... + subjunctive)

Dudo que venga. (I doubt he'll come.) No creo que sea verdad. (I don't think it's true.)

Expressing Uncertainty

No sé si... (I don't know if...) No estoy seguro/a. (I'm not sure.) No tengo certeza. (I'm not certain.) Tengo dudas. (I have doubts.) No lo sé con seguridad. (I don't know for sure.)

Possibility

Es posible que... (It's possible that... + subjunctive) Puede ser que... (It could be that... + subjunctive) Tal vez... (Perhaps... + subjunctive or indicative) Quizá(s)... (Maybe... + subjunctive or indicative) A lo mejor... (Maybe... + indicative)

Es posible que llueva. (It's possible that it will rain.) Tal vez venga mañana. (Perhaps he'll come tomorrow.)

Probability

Probablemente... (Probably...) Es probable que... (It's probable that... + subjunctive) Seguramente... (Surely/Probably...) Posiblemente... (Possibly...)

Probablemente llegue tarde. (I'll probably arrive late.) Es probable que esté en casa. (He's probably at home.)

Hedging/Softening

Creo que... (I think that...) Me parece que... (It seems to me that...) Diría que... (I would say that...) Supongo que... (I suppose that...) Imagino que... (I imagine that...)

Supongo que tienes razón. (I suppose you're right.)

Speculation

Será que... (Could it be that...?) ¿Será posible que...? (Could it be possible that...?) Me pregunto si... (I wonder if...) No me extrañaría que... (It wouldn't surprise me if... + subjunctive)

Me pregunto si vendrá. (I wonder if he'll come.)

Expressing "Maybe"

Puede ser. (Maybe / Could be.) Quizás. (Maybe.) Tal vez. (Perhaps.) A lo mejor. (Maybe.) Quién sabe. (Who knows.)

Not Knowing

No tengo ni idea. (I have no idea.) No sé. (I don't know.) No lo sé. (I don't know it.) No estoy enterado/a. (I'm not informed.) Ni idea. (No idea.)

Asking About Certainty

¿Estás seguro/a? (Are you sure?) ¿Estás completamente seguro/a? (Are you completely sure?) ¿No tienes dudas? (Don't you have doubts?) ¿Cómo lo sabes? (How do you know?)

Expressing Reservations

No estoy convencido/a. (I'm not convinced.) Tengo mis reservas. (I have my reservations.) No me convence del todo. (It doesn't totally convince me.) Vamos a ver. (Let's see / We'll see.)

Contrasting Certainty and Doubt

Certainty (+ indicative): Creo que viene. (I think he's coming.) Estoy seguro de que es verdad. (I'm sure it's true.)

Doubt (+ subjunctive): No creo que venga. (I don't think he's coming.) No estoy seguro de que sea verdad. (I'm not sure it's true.)

Levels of Certainty

Very certain: Sin duda. (Without a doubt.) Definitivamente. (Definitely.) Estoy absolutamente seguro/a. (I'm absolutely sure.)

Somewhat certain: Creo que sí. (I think so.) Probablemente. (Probably.)

Uncertain: No estoy seguro/a. (I'm not sure.) Puede ser. (Could be.)

Very uncertain: No tengo ni idea. (I have no idea.) Quién sabe. (Who knows.)

Practice