Nước ép này rất ngọt.

A word-by-word breakdown is:

• nước ép = juice
  • literally, nước is water/liquid
  • ép means pressed
  • together, nước ép means juice
• này = this
• rất = very
• ngọt = sweet

So the sentence structure is basically:

juice + this + very + sweet

which corresponds to natural English This juice is very sweet.

In Vietnamese, demonstratives like this, that, these/those usually come after the noun.

So:

• nước ép này = this juice
• literally: juice this

This is normal Vietnamese word order. English puts this before the noun, but Vietnamese usually puts này after it.

A few similar examples:

• cái bàn này = this table
• người đó = that person
• cuốn sách này = this book

Vietnamese often does not use a verb like to be when describing something with an adjective.

In English, you say:

• This juice is very sweet.

In Vietnamese, you simply say:

• Nước ép này rất ngọt.

So ngọt works like a predicate adjective/stative verb here. This is very common in Vietnamese.

Compare:

• Trà này nóng. = This tea is hot.
• Cô ấy đẹp. = She is beautiful.
• Phim này hay. = This movie is good/interesting.

It is usually described as an adjective meaning sweet, but in sentences like this it behaves a lot like a stative verb.

That is why Vietnamese does not need is before it.

So in:

• Nước ép này rất ngọt

ngọt is the main descriptive word of the sentence: to be sweet / sweet.

For learners, the easiest way to think of it is:

• ngọt = sweet
• and Vietnamese adjectives can often stand directly as the predicate

Rất means very, and it usually goes before the adjective or stative verb it modifies.

So:

• rất ngọt = very sweet
• rất ngon = very delicious
• rất đẹp = very beautiful

In this sentence:

• Nước ép này rất ngọt = This juice is very sweet

If you remove rất, the sentence becomes:

• Nước ép này ngọt = This juice is sweet

Usually, no, not if you specifically mean juice.

• nước ép = juice
• nước by itself usually means water, liquid, or sometimes drink/beverage depending on context

So if you say:

• Nước này rất ngọt

it usually sounds more like This drink/liquid is very sweet or possibly This water is very sweet, depending on context, not specifically This juice is very sweet.

If you want to be clear, nước ép is the better choice.

A rough pronunciation guide is:

• Nước → approximately noo-uhk with a broken/heavy tone
• ép → approximately ep with a sharp rising tone
• này → approximately nye with a falling tone
• rất → approximately zut in the North / often closer to yak/zak depending on accent, with a sharp tone stop
• ngọt → approximately ngawt with a heavy stopped tone

A few pronunciation notes:

• ng at the beginning of ngọt is like the ng sound in sing, but at the start of the syllable.
• Vietnamese tones matter a lot. Changing the tone can change the word.
• Pronunciation differs somewhat between Northern and Southern accents, but the sentence is standard and understood everywhere.

Yes, it is completely natural and standard.

Nước ép này rất ngọt is a normal everyday sentence. It sounds like something you would say when tasting juice and commenting on it.

Depending on tone and context, a native speaker might also say:

• Nước ép này ngọt quá. = This juice is too sweet / so sweet.
• Nước ép này ngọt lắm. = This juice is very sweet.
• Nước ép này hơi ngọt. = This juice is a bit sweet.

But your original sentence is perfectly natural.

They are similar, but not identical:

• rất ngọt = very sweet
  • neutral, straightforward
• ngọt lắm = very sweet
  • often a bit more conversational or emphatic
• ngọt quá = too sweet or so sweet
  • can mean excessiveness or strong reaction, depending on context

So:

• Nước ép này rất ngọt = a neutral statement
• Nước ép này ngọt lắm = very natural spoken emphasis
• Nước ép này ngọt quá = often suggests it is sweeter than expected, possibly overly sweet

No, that would not be the normal word order for this meaning.

To say this juice, Vietnamese normally uses:

• nước ép này

not:

• này nước ép

So the correct sentence is:

• Nước ép này rất ngọt

Vietnamese demonstratives usually follow the noun, so it is best to learn the pattern:

• noun + này = this + noun
• noun + đó/kia = that + noun

No, not in this sentence.

When talking about juice as a substance or drink in general, nước ép này is fine and natural.

A classifier would be used if you were talking about a specific container/unit, for example:

• Ly nước ép này rất ngọt. = This glass of juice is very sweet.
• Chai nước ép này rất ngọt. = This bottle of juice is very sweet.

But for simply this juice, no classifier is needed.

Yes. The basic meaning stays the same, but context can change the nuance a little.

It could mean:

• the juice tastes pleasantly sweet
• the juice is sweeter than expected
• the speaker is just describing it objectively

Vietnamese often relies on context and tone of voice for extra meaning. If someone says it with a happy voice, it may sound like praise. If they say it with concern, it may suggest the juice is overly sweet.

So the sentence itself is simple, but the speaker’s tone can add nuance.