Ese comentario fue tonto.

Ese means that, while este means this.

So:

• ese comentario = that comment
• este comentario = this comment

In Spanish, ese usually points to something a bit removed from the speaker, whether physically or mentally. In a sentence like this, it often refers to a comment already mentioned or one the speaker wants to distance themselves from.

In Spain, learners may also notice the fuller three-way contrast:

• este = this
• ese = that
• aquel = that over there / that one further away

Because comentario is a masculine noun in Spanish. Its gender is grammatical, not based on whether the thing is male or female.

So you say:

• el comentario
• ese comentario
• un comentario tonto

Even though many nouns ending in -o are masculine, this is still something you ultimately learn with each noun.

Adjectives in Spanish usually agree with the noun they describe in gender and number.

Here, tonto describes comentario, which is:

• masculine
• singular

So the adjective must also be masculine singular:

• comentario tonto

Compare:

• comentario tonto = silly/stupid comment
• idea tonta = silly/stupid idea

Because idea is feminine, the adjective changes to tonta.

Because ese already works as a determiner, like that in English.

So:

• ese comentario = that comment

You would not normally say el ese comentario. That would be wrong.

In Spanish, demonstratives like este, ese, aquel usually take the place of an article:

• el comentario = the comment
• ese comentario = that comment

Fue is the preterite form of ser for él/ella/usted.

Here the subject is ese comentario, which is grammatically third-person singular, so Spanish uses:

• fue = was

The infinitive is ser.

A quick pattern:

• yo fui
• tú fuiste
• él/ella/usted fue
• nosotros fuimos
• vosotros fuisteis
• ellos/ellas/ustedes fueron

So Ese comentario fue tonto literally has the same verb form as It was silly/stupid.

This is one of the most common questions.

Both fue and era can translate as was, but they are used differently:

• fue = preterite, often presenting something as a completed event or judgment
• era = imperfect, often giving background, description, or an ongoing past situation

With Ese comentario fue tonto, the speaker is judging a specific comment as a completed thing: That comment was stupid/silly.

If you said Ese comentario era tonto, it would sound less natural in most ordinary contexts, because a comment is usually a single completed remark, not an ongoing background state. Spanish normally prefers fue here.

So for a one-off remark, fue is the natural choice.

Because Spanish uses ser to identify or characterize something, including giving a judgment like stupid, silly, important, cruel, etc.

Here, the sentence is classifying the comment:

• Ese comentario fue tonto.

Using estar would sound wrong here. Estar is usually for states, conditions, locations, and certain context-dependent meanings, but not for this kind of basic evaluation of a comment.

So:

• ser tonto = to be silly/stupid
• estar tonto can exist, but it means something more like to be acting silly / not thinking clearly at the moment, and it is used for people, not naturally for comentario in this sentence.

It can mean either, depending on context and tone.

Tonto is often a bit softer than estúpido. Depending on the situation, it can mean:

• silly
• foolish
• stupid
• dumb

So Ese comentario fue tonto could be:

• That comment was silly
• That comment was stupid

In many contexts, tonto feels less harsh than estúpido, though tone of voice matters a lot.

It can be.

The sentence criticizes the comment, not necessarily the person, so it is often less direct than saying someone is stupid:

• Ese comentario fue tonto. = That comment was stupid/silly.
• Eres tonto. = You are stupid/silly.

So this sentence is definitely negative, but it may sound more like criticism of what was said rather than an insult against someone's whole character.

Still, depending on tone and context, it can sound blunt.

Yes, but the normal, neutral order is:

• Ese comentario fue tonto.

Spanish allows some flexibility, but changing the order usually changes emphasis.

For example:

• Fue tonto ese comentario.

This is possible, but it sounds more marked, as if you are emphasizing the judgment fue tonto.

For learners, the safest and most natural version is the original one.

Fue is pronounced roughly like fweh in one syllable.

A simple guide for the whole sentence:

• Ese ≈ EH-seh
• comentario ≈ ko-men-TA-rio
• fue ≈ fweh
• tonto ≈ TON-to

In standard Spain Spanish, tonto has a clear t sound, and comentario has the stress on ta: comenTArio.

No, not normally.

In Spanish, a singular countable noun usually needs some kind of determiner, such as:

• el comentario
• un comentario
• ese comentario
• mi comentario

So:

• Ese comentario fue tonto. = correct
• Un comentario fue tonto. = possible, but means A comment was silly
• Comentario fue tonto. = not natural/incorrect in normal Spanish

Yes. That is a very natural alternative.

• Ese comentario fue tonto. = That comment was silly/stupid.
• Ese comentario fue una tontería. = That comment was nonsense / a stupid thing to say.

The second version uses a noun phrase (una tontería) instead of an adjective (tonto). Both are common, but fue una tontería can sound especially idiomatic in everyday Spanish.