Adjectives followed by 'que' or by 'de que'

[pierrre]

Not sure when "seguro" should be followed by 'que' or 'de que'. The truth is that I have seen it followed by both. I have a similar question with 'que' and 'de que' when I use the word "sorprendido". Confident that someone in the forum can help me with this.

[AngelicaDeAlquezar]

Many people avoid "de que", because they think that the "dequeísmo" is a mistake in all cases. However, when the sentence corresponds to the general formula "estar seguro de algo", the preposition should go with the conjunction:

·Estoy seguro de que Pedro no vino. (I'm certain that Pedro didn't come.)
·No estamos seguros de que seas honesto. (We're not certain that you're honest.)
·¿Estás seguro de que quieres subir al avión? (Are you sure you want to get on the plane?)

"Que" doesn't need "de" when:

·¿Es seguro que vamos a ganar? (Is it for sure that we'll win?)
·Lo más seguro es que nieve hoy. (I'm pretty sure that it will snow today.)


As for "sorprendido", it's the same when the general formula is "Estar sorprendido de algo":
·Estaban sorprendidos de que llegara a la fiesta. (They were very surprised that he/she/I arrived to the party.)
·No estoy sorprendido de que se haya descompuesto el auto. (I'm not surprised the car has broken.)

[Don José]

The truth is that I have seen it followed by both.

I'm not surprised since they are commonly mistaken. There was a time when the "dequeísmo" was common. Now the reaction, as Angelica pointed out, is the opposite ("queísmo"). Sometimes it's so nasty to watch the TV because of it. Well, not only for that reason...

[pierrre]

Thank you, Angelica and Jose, for the assistance and for sharing your observations on "queísmo" and "dequeísmo". Forgive me everyone if I seem to want to oversimplify when I summarize that "ser seguro" is followed by "que" and "estar seguro" by "de que". The fifteen year old children to whom I must explain the distinction are sometimes intolerant of the nuances in the language so I'd appreciate just a little more light on this topic.

[Don José]

Forgive me everyone if I seem to want to oversimplify when I summarize that "ser seguro" is followed by "que" and "estar seguro" by "de que".

I can't think of any exception to that rule.

I admit I started to doubt about the topic some time ago. The RAE gave me a good explanation, but I wonder whether it would be useful for non natives:

3. Un procedimiento que puede servir en muchos de estos casos para determinar si debe emplearse la secuencia de «preposición + que», o simplemente que, es el de transformar el enunciado dudoso en interrogativo. Si la pregunta debe ir encabezada por la preposición, esta ha de mantenerse en la modalidad enunciativa. Si la pregunta no lleva preposición, tampoco ha de usarse esta en la modalidad enunciativa: ¿De qué se preocupa? (Se preocupa de que...); ¿Qué le preocupa? (Le preocupa que...); ¿De qué está seguro? (Está seguro de que...); ¿Qué opina? (Opina que...); ¿En qué insistió el instructor? (Insistió en que...); ¿Qué dudó o de qué dudó el testigo? (Dudó que... o dudó de que...); ¿Qué informó [Am.] o de qué informó [Esp.] el comité? (Informó que... [Am.] o informó de que... [Esp.]).

http://buscon.rae.es/dpdI/SrvltConsulta?lema=dequeismo

There is more information about the "dequeísmo" in the link.