jeoneun pyeongsaeng dareun sarameul dopgo sipeoyo.

저 means I in a humble/polite way.
는 is the topic marker, so 저는 means something like as for me or I, personally.

In this sentence, 저는 sets up the speaker as the topic:

• 저는 평생 다른 사람을 돕고 싶어요.

In natural Korean, 저는 is often omitted if it is already clear who is speaking:

• 평생 다른 사람을 돕고 싶어요.

That sounds very natural too.

Both can mean I, but they do different jobs.

• 저는 = topic marker
• 제가 = subject marker

With 저는, the sentence feels like a general statement about yourself or your values:

• 저는 평생 다른 사람을 돕고 싶어요.
  As for me, I want to help others for life.

With 제가, there is usually more emphasis on I as the person doing it, often in contrast to someone else or as new information:

• 제가 평생 다른 사람을 돕고 싶어요.

That version is possible, but in most normal contexts 저는 sounds more natural for this kind of personal goal statement.

평생 means one’s whole life, for life, or lifelong.

In this sentence, it works adverbially, so it describes the whole action 돕고 싶어요:

• 평생 = for my whole life / throughout my life

It does not need a particle here. Korean often uses time words without particles when they function like adverbs.

So this is perfectly natural:

• 평생 다른 사람을 돕고 싶어요.

You could also say:

• 평생 동안 다른 사람을 돕고 싶어요.

Adding 동안 makes it more explicitly for the whole duration of my life, but it is not necessary.

다른 comes from the verb 다르다, which means to be different.

When Korean verbs or adjectives come before a noun, they often change form into a modifier form.
Here:

• 다르다 → 다른

So:

• 다른 사람 = a different person / another person / other people, depending on context

In this sentence, 다른 사람 means other people or others.

In Korean, the plural marker 들 is often optional, especially when the meaning is already clear.

So:

• 다른 사람을 돕고 싶어요
• 다른 사람들을 돕고 싶어요

Both can mean I want to help other people.

The version without 들 is very natural and common. Korean often leaves nouns unmarked for plural when speaking generally.

So 다른 사람을 here can still mean other people in a broad sense, not just one specific person.

을/를 is the object marker.

The verb 돕다 means to help, and the person being helped is the direct object. So:

• 다른 사람을 돕다 = to help other people

Because 사람 ends in a consonant, it takes 을:

• consonant + 을
• vowel + 를

Examples:

• 사람을 돕다
• 친구를 돕다

-고 싶어요 means want to do.

It attaches to the verb stem:

• 돕다 → stem 돕-
• 돕고 싶어요 = want to help

So the pattern is:

• verb stem + 고 싶어요

Examples:

• 가고 싶어요 = want to go
• 먹고 싶어요 = want to eat
• 돕고 싶어요 = want to help

This is the normal way to express your own desire in polite speech.

Because 돕다 is only irregular in certain situations.

돕다 is a ㅂ-irregular verb, but the irregular change happens before vowel-initial endings.

For example:

• 돕다 + 아요 → 도와요
• 돕다 + 아서 → 도와서

But -고 begins with a consonant (ㄱ), so there is no irregular change here:

• 돕다 + 고 → 돕고

So:

• 돕고 싶어요 = correct
• 도우고 싶어요 = incorrect
• 도와고 싶어요 = incorrect

A useful comparison:

• 다른 사람을 도와요 = I help other people
• 다른 사람을 돕고 싶어요 = I want to help other people

Yes. 싶어요 is a polite, everyday style. It is very common in conversation.

Here are some common levels:

• 돕고 싶어요 = polite, natural everyday speech
• 돕고 싶습니다 = more formal
• 돕고 싶어 = casual, intimate speech

So if you are speaking politely, the original sentence sounds good.

Usually, -고 싶어요 is most natural for your own wants or in questions about the listener’s wants.

So these are natural:

• 저는 돕고 싶어요. = I want to help.
• 도와주고 싶어요? = Do you want to help?

But for a third person, Korean often uses -고 싶어하다 instead:

• 그는 다른 사람을 돕고 싶어해요. = He wants to help other people.

That is because you usually cannot directly know another person’s inner desire unless you are quoting them.

Yes, you could.

• 돕다 = to help
• 도와주다 = to help someone / do someone the favor of helping

So:

• 다른 사람을 돕고 싶어요 = I want to help others.
• 다른 사람을 도와주고 싶어요 = I want to help others out.

The original 돕고 싶어요 is clean and neutral.
도와주고 싶어요 can sound a little more personal or benefactive.

The original order is very natural:

• 저는 평생 다른 사람을 돕고 싶어요.

But Korean word order is somewhat flexible as long as the particles make the roles clear.

For example, this is also possible:

• 저는 다른 사람을 평생 돕고 싶어요.

Both are understandable. The original version places 평생 earlier, which sounds smooth and natural when talking about a lifelong goal.

Yes. Very often.

If it is already obvious that you are talking about yourself, Korean normally leaves out the subject:

• 평생 다른 사람을 돕고 싶어요.

This is just as natural as the full sentence.
Korean frequently omits subjects and objects when the context makes them clear.