Trò này rất vui.

A simple breakdown is:

• trò = game, activity, trick, joke, or prank, depending on context
• này = this
• rất = very
• vui = fun, enjoyable, happy

So the structure is basically:

• trò này = this game / this activity / this joke
• rất vui = very fun / very enjoyable

In context, the whole sentence usually means This game is very fun or This is very fun.

In Vietnamese, demonstratives like này (this) usually come after the noun.

So:

• trò này = this game / this activity
• người này = this person
• nhà này = this house

This is different from English, where this comes before the noun.

A useful pattern is:

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

Vietnamese often does not use a verb like to be in sentences with adjectives.

In English, you say:

• This game is very fun

In Vietnamese, you simply say:

• Trò này rất vui

Literally, it is more like:

• This game very fun

That is completely normal in Vietnamese.

Vui can mean both happy and fun/enjoyable, depending on the sentence.

Here, in Trò này rất vui, it means something like:

• fun
• enjoyable
• amusing

Because trò is a thing, not a person, vui describes the experience of it being enjoyable.

Compare:

• Tôi rất vui. = I am very happy.
• Trò này rất vui. = This game is very fun.

So the meaning changes with context.

Trò by itself can have several meanings depending on context, such as:

• game
• activity
• prank
• trick
• joke

Trò chơi is a more explicit and common way to say game.

So:

• Trò này rất vui can mean This game/activity/joke is very fun
• Trò chơi này rất vui more clearly means This game is very fun

If you specifically mean a game, trò chơi này is often clearer for learners.

Rất means very and strengthens the adjective.

• Trò này vui. = This is fun.
• Trò này rất vui. = This is very fun.

Yes, you can leave it out if you do not want the extra emphasis.

One small note: in natural spoken Vietnamese, people do sometimes omit rất and rely on tone of voice or other words for emphasis.

A rough English-friendly guide is:

• trò ≈ chaw or jaw with a low falling tone
• này ≈ nye with a falling tone
• rất ≈ something like zut or rut depending on accent, with a sharp tone
• vui ≈ voo-ee or vwee

A few important pronunciation notes:

• tr in southern speech may sound closer to ch for many learners.
• rất is tricky because the â vowel is short and the final t is unreleased.
• vui is one syllable with a glide, not two fully separate syllables.

If you are learning a specific accent, pronunciation will differ a bit between northern and southern Vietnamese.

Yes, it is natural, but the exact naturalness depends on what trò refers to.

It sounds fine if you are talking about:

• a game
• an activity
• a joke
• some playful thing

If you specifically mean game, many speakers might also say:

• Trò chơi này rất vui.

That version is a little clearer and more explicit.

So Trò này rất vui is natural, but context matters.

Yes, it can.

Because trò can mean more than just game, trò này may sometimes mean:

• this trick
• this prank
• this stunt
• this behavior

For example, in another context, trò này could sound disapproving, like this nonsense or this little trick.

But in Trò này rất vui, the adjective vui makes the sentence sound positive, so the listener will usually understand it as something enjoyable or amusing.

A few common patterns:

• Trò này không vui. = This is not fun.
• Trò này có vui không? = Is this fun?
• Trò này vui không? = Is this fun?
• Trò này có rất vui không? is less natural; usually you ask about vui, not rất vui

So the most useful versions are:

• không for negation
• ... không? for yes/no questions

Yes, you can say Cái trò này rất vui, but it has a slightly different feel.

Cái is a classifier often used with objects and sometimes with certain expressions. In some cases, adding cái can make the noun phrase feel more concrete or conversational.

Compare:

• Trò này rất vui.
• Cái trò này rất vui.

The second can sound more colloquial, but depending on context, cái trò này can also sound a bit marked or emotional. In some situations, it might even sound like this stunt/trick rather than a neutral this game.

So for a beginner, Trò này rất vui is a safe and simple choice.