Tu assures Paul, n’est-ce pas ?

Because the subject is tu.

The verb is assurer, a regular -er verb. In the present tense, its forms are:

• j’assure
• tu assures
• il / elle / on assure
• nous assurons
• vous assurez
• ils / elles assurent

So tu assures Paul means you assure Paul.

Also, the final -s in assures is normally not pronounced.

Grammatically, assurer is a regular -er verb.

In this sentence, it is being used with a direct object, which is Paul. That means the structure is:

• Tu = subject
• assures = verb
• Paul = direct object

So the sentence follows a very common French word order:

subject + verb + object

Because French usually keeps the normal order subject + verb + object in ordinary statements and many questions.

So:

• Tu assures Paul.
• literally: You assure Paul.

English does the same in a basic statement: You reassure Paul or You assure Paul.

French does not move Paul in this kind of sentence.

By itself, Tu assures Paul is a statement.

It becomes a question here because of the tag n’est-ce pas ?, which turns it into something like:

• ..., isn’t that so?
• ..., right?

So the speaker is not asking for completely new information in a neutral way. They are asking for confirmation.

N’est-ce pas ? is a very common French tag question.

It is added to the end of a sentence to mean something like:

• isn’t that right?
• right?
• isn’t that so?

So:

• Tu assures Paul, n’est-ce pas ?

means the speaker believes this is true and wants the other person to confirm it.

Because French often uses one fixed tag expression: n’est-ce pas ?

English tag questions change depending on the verb and subject:

• You know him, don’t you?
• He is here, isn’t he?
• They left, didn’t they?

French often avoids that whole system and simply uses:

• ..., n’est-ce pas ?

So it works as a general confirmation tag.

Literally, it breaks down as:

• n’ est-ce pas
• is it not

More naturally, that becomes:

• isn’t it?
• isn’t that so?

Even though the literal wording is singular and impersonal, in real use it works as a general tag after many different kinds of sentences.

No.

You could also ask a yes/no question in other ways, for example with intonation:

• Tu assures Paul ?

That is common in spoken French.

But the meaning is slightly different in tone:

• Tu assures Paul ? = a straightforward yes/no question
• Tu assures Paul, n’est-ce pas ? = a confirmation question; the speaker expects the answer to be yes

So n’est-ce pas often sounds a little more like right?

It is often felt to be a bit more careful, neutral, or sometimes slightly formal compared with very casual spoken tags.

In everyday speech, people may also say things like:

• ..., non ?
• ..., hein ?

For example:

• Tu assures Paul, non ?

That is more conversational.

But n’est-ce pas ? is absolutely normal and widely understood.

Because n’est-ce pas is added as a separate tag at the end of the sentence.

The comma shows a small pause:

• Tu assures Paul, n’est-ce pas ?

In speech, you usually hear that little break before the tag.

A careful approximation is:

• ty a-syur pol, nayss-pa

More accurately in IPA:

• [ty a.syʁ pɔl nɛs pa]

A few helpful points:

• tu sounds like ty
• assures has a pronounced a at the start
• the final -s in assures is silent
• Paul is pronounced roughly like pohl
• in n’est-ce pas, the t of est is not pronounced here

No special liaison is needed here.

Tu already ends in a vowel sound, so you simply go from:

• tu → assures

as:

• [ty a.syʁ]

The important thing for learners is that the written -s in assures is silent.

Tu is the familiar singular form of you.

You use tu with:

• one person
• someone you know well
• a friend
• a child
• a family member
• sometimes a coworker or classmate, depending on context

You use vous for:

• one person in a formal or polite situation
• more than one person

So if you were speaking politely to one person, you would say:

• Vous assurez Paul, n’est-ce pas ?

Yes, in principle you can make yes/no questions by inversion in French, but with tu and an ordinary lexical verb, that sounds more formal or literary.

For example:

• Assures-tu Paul ?

That is grammatical, but it is not the most natural everyday version in many situations.

In normal speech, French often prefers:

• Tu assures Paul ?
• Tu assures Paul, n’est-ce pas ?

Yes. In grammar terms, Paul is the direct object of assurer here.

So Paul is the person the action is directed toward.

That is why there is no preposition before Paul.

Yes.

A direct object pronoun would normally go before the verb in French.

So Paul could become le if it refers to a masculine singular person:

• Tu le assures is not correct French word order.

The correct structure would be:

• Tu l’assures, n’est-ce pas ?

Notice two things:

1. the pronoun goes before the verb
2. le becomes l’ before a vowel sound

Yes, the structure is natural.

The main thing to keep in mind is tone:

• Tu assures Paul ? sounds like a simple spoken question
• Tu assures Paul, n’est-ce pas ? sounds like the speaker expects confirmation

So it is natural if the context is one where the speaker is checking something they think is true.