Negative declarations of certainty (non so che)

Negative Certainty and Doubt

When you declare that you are certain about something, you use the indicative mood to state a fact. However, stating that you are not certain introduces doubt. Because of this, negative declarations of certainty and knowledge must be followed by che (that) and the subjunctive mood.

Personal Doubt

To express that you personally lack certainty about a clue or puzzle, use phrases like:

• Non ho la certezza che... (I am not certain that...)
• Non sono convinto che... (I am not convinced that...)
• Non sono sicuro che... (I am not sure that...)

Notice how the verbs in the dependent clauses below (apra, sia, seguano) take the subjunctive mood.

Impersonal Doubt

The same rule applies to impersonal expressions. When you state that a fact isn't obviously true or guaranteed, the following clause takes the subjunctive. Common phrases include:

• Non è lampante che... (It is not blatant that...)
• Non è sicuro che... (It is not certain that...)