Công việc này cần nhiều sức.

A natural word-by-word breakdown is:

• công việc = work, job, task
• này = this
• cần = need, require
• nhiều = much, a lot of, many
• sức = strength, energy, effort

So the structure is basically:

• Công việc này = this job / this task
• cần nhiều sức = requires a lot of strength/effort

Vietnamese often builds meaning very directly like this, without extra linking words.

In Vietnamese, demonstratives like này (this) usually come after the noun, not before it.

So:

• công việc này = this job/task
• literally: job/task this

This is very normal Vietnamese word order. Compare:

• người này = this person
• cuốn sách này = this book
• nhà này = this house

So if you are thinking in English word order, it may feel reversed, but in Vietnamese it is standard.

Vietnamese often does not use a verb like English to be in sentences like this.

English:

• This job is hard
• This job requires a lot of effort

Vietnamese can often say things more directly:

• Công việc này khó.
• Công việc này cần nhiều sức.

There is no need to insert là here. In fact, là would usually be wrong in this sentence.

So Công việc này cần nhiều sức is a complete sentence without any word meaning is.

Cần means to need or to require.

In this sentence, it means the job/task requires a lot of strength or effort.

Examples:

• Tôi cần tiền. = I need money.
• Việc này cần thời gian. = This task requires time.
• Công việc này cần nhiều sức. = This job requires a lot of effort/strength.

So cần can work for both personal needs and general requirements.

Sức literally relates to strength, energy, or stamina.

In cần nhiều sức, it often suggests:

• physical strength,
• energy,
• or a lot of exertion/effort.

Depending on context, it may sound like:

• This job takes a lot of physical effort
• This work requires a lot of energy

If you want to be more specific, Vietnamese can use:

• sức lực = strength, physical energy
• thể lực = physical fitness/physical strength
• công sức = effort, labor put into something

But sức by itself is common and natural in everyday speech.

Yes, cần nhiều sức is understandable and natural, especially in everyday speech. It means the work requires a lot of strength/effort.

However, Vietnamese speakers might also say:

• Công việc này tốn sức. = This job is tiring / takes effort.
• Công việc này tốn nhiều sức. = This job takes a lot of effort.
• Công việc này cần nhiều sức lực. = This job requires a lot of strength.
• Công việc này rất vất vả. = This job is very demanding / exhausting.

So your sentence is good, but there are several nearby ways to express the same idea.

Yes. Việc này cần nhiều sức is also natural.

The difference is:

• việc = thing to do, task, matter, work
• công việc = job, work, task, often a bit more formal or specific as work/job

So:

• Việc này cần nhiều sức = This task/thing requires a lot of effort.
• Công việc này cần nhiều sức = This job/task requires a lot of effort.

In many contexts, both work.

In Vietnamese, nhiều is used very broadly for both:

• many countable things
• much / a lot of uncountable things

So it works with nouns like:

• nhiều người = many people
• nhiều tiền = a lot of money
• nhiều thời gian = a lot of time
• nhiều sức = a lot of strength/energy

You do not need a separate word like English much here. Nhiều covers that idea.

It depends on context.

Công việc can mean:

• a job
• a piece of work
• a task
• work in general

So Công việc này cần nhiều sức could mean:

• This job requires a lot of strength
• This task takes a lot of effort
• This work is physically demanding

English translation depends on the situation. Vietnamese often leaves that a bit flexible.

A rough pronunciation guide is:

• Công ≈ kohng
• việc ≈ vee-uht / vee-ək with a clipped ending
• này ≈ nye or nai depending on accent
• cần ≈ kuhn
• nhiều ≈ nyee-uh
• sức ≈ sook with a short, stopped ending

A few important points:

• việc, cần, and sức all carry tones, so tone matters.
• nhiều begins with nh, a sound similar to Spanish ñ or the ny in canyon.
• Final consonants in Vietnamese are often shorter and more clipped than in English.

If you are learning pronunciation, it is best to copy native audio rather than rely only on English spelling.