Eu não sei a verdade.

I do not know the truth.

Breakdown of Eu não sei a verdade.

• eu: I
• não: not
• a verdade: the truth
• saber: to know how to

Questions & Answers about Eu não sei a verdade.

Can I drop Eu and just say Não sei a verdade?

Yes. In Portuguese, the subject pronoun is often omitted because the verb ending (sei) already shows the subject is eu (I).

• Eu não sei a verdade and Não sei a verdade both mean the same thing.
• Saying Eu adds a bit more emphasis to I (like stressing “I don’t know the truth”).
• In neutral, everyday speech you’ll probably hear Não sei a verdade a lot.

Why is the negative word não placed before sei?

In Portuguese, the basic rule is:

não + conjugated verb

So:

• Eu não sei a verdade. (correct)
• Eu sei não a verdade. (incorrect)

Não almost always comes directly before the main finite verb in simple sentences. If there are object pronouns, não generally comes before them too:

• Eu não a sei. = “I don’t know it.” (here a = it, referring to a verdade)

Why do we say sei and not something like sabo?

Because sei is an irregular form of the verb saber (to know). Present tense:

• eu sei – I know
• tu sabes – you know (informal singular, rare in much of Brazil)
• ele / ela / você sabe – he / she / you (formal or general) know
• nós sabemos – we know
• vocês / eles / elas sabem – you (plural) / they know

There is no form sabo in standard Portuguese.
So Eu não sei a verdade is the only correct present-tense way to say “I don’t know the truth.”

What’s the difference between saber and conhecer? Why not Eu não conheço a verdade?

Portuguese has two common verbs for “to know”:

• saber – to know a fact, information, how to do something
  
  • Eu sei a verdade. = I know the truth.
  • Eu sei falar português. = I know how to speak Portuguese.
• conhecer – to be familiar with or acquainted with people, places, works, etc.
  
  • Eu conheço o João. = I know João.
  • Eu conheço o Brasil. = I know / am familiar with Brazil.

A verdade (“the truth”) is a piece of information, so you use saber:

• Eu não sei a verdade. ✔
• Eu não conheço a verdade. sounds strange and unnatural in this context.

Why is there an article a before verdade? Could I say Eu não sei verdade?

In Portuguese, abstract nouns like verdade (truth), amor (love), liberdade (freedom) often take the definite article when you talk about them in a concrete, specific way.

• Eu não sei a verdade. = I don’t know the truth (a specific truth).

Saying Eu não sei verdade is ungrammatical in standard Portuguese.
You generally need a verdade here.

You could sometimes see verdade without an article in very special contexts (titles, slogans, certain set phrases), but not in a simple sentence like this.

Why is it a verdade and not o verdade? How do I know the gender?

Verdade is a feminine noun, so it takes the feminine article a:

• a verdade = the truth
• uma verdade = a truth

In Portuguese, most nouns ending in -ade are feminine:

• a cidade (city)
• a liberdade (freedom)
• a vontade (will, desire)

So by learning the word as a verdade, you automatically learn its gender.

Is eu always capitalized like I in English?

No. This is a major difference.

• In English, I is always capitalized.
• In Portuguese, eu is only capitalized when it appears at the beginning of a sentence or in titles, just like any other word.

So:

• Eu não sei a verdade. (start of sentence, capital E)
• Ele disse que eu não sei a verdade. (middle of sentence, eu is lowercase)

Could this sentence mean “I didn’t know the truth” instead of “I don’t know the truth”?

No, not as it stands. Sei is present tense, so it refers to now.

• Eu não sei a verdade. = I don’t know the truth (now).

For the past, you’d change the verb form:

• Eu não sabia a verdade. = I didn’t know / didn’t use to know the truth (background, ongoing in the past).
• Eu não soube a verdade. = I didn’t find out / I never got to know the truth (completed event, “I ended up not knowing”).

So the tense of saber is important and changes the meaning.

Can I say Eu não sei nada? Is that a double negative?

Yes, and it’s perfectly correct and very common.

• Eu não sei nada. = Literally “I don’t know nothing,” but it means “I don’t know anything.”

Portuguese allows and requires this kind of double negative:

• Eu não vejo ninguém. = I don’t see anybody.
• Eu não sei nada. = I don’t know anything.

Unlike in standard English, this is not considered incorrect in Portuguese; it’s the normal grammar.

Is there any difference between Eu não sei a verdade and Eu não sei da verdade?

Yes, there’s a nuance.

• Eu não sei a verdade.
  Focuses on possessing the truth as information: you don’t know what the truth is.

• Eu não sei da verdade.
  Literally “I don’t know of the truth.” It can mean you are not aware of the truth, or you haven’t heard about it. It sounds more like “I don’t know about the truth” / “I haven’t heard the truth.”

In most standard contexts where English says “I don’t know the truth,” you use Eu não sei a verdade.

How do I pronounce não and what does the squiggle (~) mean?

The ~ (tilde) over ã in não shows that the vowel is nasal.

• não is roughly like “now” but with the vowel going through your nose and ending in a nasal sound.
• Don’t pronounce it like English “non” or “no.”

Very roughly in English-friendly terms:

• não ≈ “nowng” (short, nasal “ow” + nasal ending)

The tilde appears in words like:

• não (not)
• irmã (sister)
• maçã (apple)

Can this sentence be turned into a question without changing the word order?

Yes. Portuguese often keeps the same word order and just changes the intonation (and/or punctuation) to make a question:

• Eu não sei a verdade. (statement, falling intonation)
• Eu não sei a verdade? (question, rising intonation) – implies surprise, like “I don’t know the truth?”

For a neutral information question (“What is the truth? I don’t know it.”), you’d more likely rephrase:

• Qual é a verdade? Eu não sei. = “What is the truth? I don’t know.”

Can I just say Eu não sei without a verdade?

Yes. Eu não sei simply means “I don’t know,” and it’s very common, especially when the context already makes clear what you don’t know.

For example:

• Qual é a verdade? – What is the truth?
  Eu não sei. – I don’t know.

Adding a verdade just makes it explicit in the same sentence:

• Eu não sei a verdade. – I don’t know the truth.