Việc này khiến tôi mệt.

Việc này means this matter, this task, or this thing/situation, depending on context.

In this sentence, việc does not just mean job in the employment sense. It often means:

• a matter
• an affair
• a task
• something that is happening or needs to be dealt with

So việc này is a fairly neutral way to refer to this matter / this issue / this thing.

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

So:

• việc này = this matter
• người này = this person
• cuốn sách này = this book

This is a very common word order difference from English.

Việc is the noun being pointed to, and này specifies it as this one.

You usually need some noun here. Saying just này by itself would not work in this sentence.

Depending on context, Vietnamese could use other nouns instead:

• chuyện này = this matter / this story / this issue
• điều này = this thing / this point / this fact
• cái này = this thing

Among these, việc này suggests a matter, task, or situation rather than a physical object.

Khiến means to cause, to make, or to lead someone to be in a certain state.

The pattern here is:

[cause] + khiến + [person] + [state]

So in this sentence:

• Việc này = the cause
• khiến = causes/makes
• tôi = the person affected
• mệt = the resulting state

This is a common causative structure in Vietnamese.

Yes. Việc này làm tôi mệt is also natural.

The difference is mainly style:

• làm is very common and everyday
• khiến can sound a bit more formal, written, or deliberate

Both are correct. In many situations, learners will hear làm tôi mệt more often in speech.

Because Vietnamese often uses adjectives directly as predicates, without a separate verb like to be.

So:

• Tôi mệt = I am tired
• Anh ấy vui = He is happy
• Cô ấy đẹp = She is beautiful

In this sentence, mệt is the state that tôi ends up in. Vietnamese does not need an extra word equivalent to am here.

Yes, functionally it is the person affected by the action of khiến.

You can think of the structure like this:

• Việc này = subject / cause
• khiến = makes / causes
• tôi = affected person
• mệt = tired

So tôi is the experiencer: the one who becomes tired because of việc này.

Both are possible, but they are slightly different in feel.

• mệt = tired
• mệt mỏi = tired, exhausted, weary; often a bit stronger or more descriptive

So:

• Việc này khiến tôi mệt = This makes me tired
• Việc này khiến tôi mệt mỏi = This makes me feel exhausted / weary

The shorter mệt is very common and natural.

It can be either, depending on context.

Mệt can mean:

• physically tired
• mentally drained
• worn out in a general sense

So this sentence could mean:

• the task is physically tiring
• the situation is emotionally or mentally exhausting
• both

Vietnamese often leaves that for context to clarify.

Yes, you could.

• Việc này khiến tôi mệt focuses on the cause and presents it as something that makes you tired.
• Tôi mệt vì việc này focuses first on your state (I’m tired) and then gives the reason (because of this matter).

So the difference is mainly one of emphasis:

• Việc này khiến tôi mệt = This matter is making me tired.
• Tôi mệt vì việc này = I’m tired because of this matter.

Both are natural.

It is natural and correct. It sounds neutral and clear.

That said, in everyday speech, people might also say:

• Việc này làm tôi mệt
• Chuyện này làm tôi mệt
• Tôi mệt vì việc này

So your sentence is perfectly good, but khiến may sound slightly more formal than the most casual spoken alternative.

They can all be translated similarly, but they are not exactly the same.

• việc này: this matter, this task, this affair
  
  • often used for something practical, actionable, or situational
• chuyện này: this matter, this story, this issue
  
  • often more conversational and broad
• điều này: this thing, this point, this fact
  
  • often more abstract or formal

So:

• Việc này khiến tôi mệt sounds like a task or matter is tiring
• Chuyện này khiến tôi mệt sounds a bit more conversational
• Điều này khiến tôi mệt can sound more abstract or formal

All three can work, but việc này is a good neutral choice if you mean a matter or task.