Đảo này rất đẹp.

In Vietnamese, words like this and that usually come after the noun, not before it.

So:

• đảo này = this island
• đảo đó / đảo kia = that island

This is a very common word-order difference from English.

Vietnamese often does not use a word meaning to be before adjectives.

So instead of saying something like This island is very beautiful with a separate is, Vietnamese simply says:

• Đảo này rất đẹp

That is the normal pattern: noun phrase + adverb + adjective.

If you add là here, it sounds unnatural. Là is mainly used when one noun is identified as another noun, for example:

• Đây là đảo nhỏ. = This is a small island.

Rất means very. It intensifies the adjective that follows it.

So:

• đẹp = beautiful
• rất đẹp = very beautiful

It goes before the adjective, just like very in English.

It is basically an adjective, meaning beautiful. But in Vietnamese, adjectives can often act like the main predicate of a sentence, without needing a separate word for is.

So in grammar explanations, you may also hear people say that đẹp behaves like a stative verb here.

For a learner, the important point is:

• đẹp describes the island
• no extra is is needed

Not necessarily. Đảo này rất đẹp is completely natural.

But you may also hear:

• Hòn đảo này rất đẹp.

Here, hòn is a classifier often used with islands and some natural objects. It can make the noun phrase sound a bit fuller or more explicit.

So both are possible:

• Đảo này rất đẹp.
• Hòn đảo này rất đẹp.

Vietnamese does not use articles the way English does. There is no direct equivalent of the or a/an in most sentences.

Whether something is definite or indefinite is usually understood from context, or shown by other words such as:

• này = this
• đó / kia = that
• một = one, a/an in some contexts

So đảo này already clearly means a specific island: this island.

Each word has its own tone:

• đảo: hỏi tone
• này: huyền tone
• rất: sắc tone
• đẹp: nặng tone

A rough guide:

• đảo: a dipping tone
• này: a low falling tone
• rất: a rising tone
• đẹp: a low, short, heavy tone

So the sentence has quite a bit of tonal contrast, which is good to practice carefully, one word at a time.

This is important for English speakers.

• rất ends in -t
• đẹp ends in -p

In Vietnamese, final -t and -p are usually unreleased. That means your mouth closes for the consonant, but you do not strongly release it the way English often does.

So:

• rất should end abruptly
• đẹp should also end abruptly

Try not to add an extra vowel after them. They should not sound like ra-tuh or dep-uh.

Yes. You can change the demonstrative depending on meaning.

Common choices are:

• này = this
• đó = that
• kia = that over there
• ấy = that (more formal or written in some contexts)

So you could also say:

• Đảo đó rất đẹp.
• Đảo kia rất đẹp.

The grammar stays the same.

Then you would build a noun phrase, not a complete statement.

A natural pattern is:

• đảo đẹp này
• hòn đảo đẹp này

Vietnamese usually puts the adjective after the noun, and the demonstrative này comes near the end of the noun phrase.

So compare:

• Đảo này rất đẹp. = This island is very beautiful.
• Đảo đẹp này = this beautiful island

You can also say:

• hòn đảo rất đẹp này = this very beautiful island

Yes. If you remove rất, the sentence still works:

• Đảo này đẹp.

That simply means This island is beautiful.

Adding rất makes it stronger:

• Đảo này rất đẹp. = This island is very beautiful.

So rất is optional; it just changes the degree.

Yes. In conversation, Vietnamese speakers often use other intensifiers besides rất.

For example:

• Đảo này đẹp lắm. = This island is very beautiful / really beautiful.
• Đảo này đẹp quá. = This island is so beautiful.

These can sound more expressive or conversational than rất đẹp, depending on context. But Đảo này rất đẹp is perfectly correct and neutral.