Learn Spanish (Spain): Creo que es una tontería negar esto. - I think that it is nonsense to deny this.

Yes, you could say Para mí, es una tontería negar esto (In my opinion, it is nonsense to deny this). Both creo que and para mí are great ways to express your opinion. Para mí highlights your personal perspective, while creo que states what you believe to be true.

Why is the verb es in the indicative mood rather than the subjunctive?

Affirmative statements using verbs of belief like creer take the indicative mood because you are declaring what you consider to be a reality. You would only use the subjunctive if the phrase were negative, such as No creo que sea una tontería (I do not think it is nonsense).

Why does the Spanish sentence use una tontería when the English translation just says 'nonsense'?

In English, 'nonsense' is generally an uncountable concept. In Spanish, tontería refers to a specific foolish thought or action, making it a countable noun. Therefore, it needs the article una to express that it is 'a piece of nonsense' or 'a foolish thing'.

Why is esto used here instead of este or esta?

The word esto is a neuter pronoun. You use it when referring to an abstract idea, a general statement, or a situation rather than a specific masculine or feminine noun. Here, it refers to the general concept of what is being denied.