Iya, saya setuju dengan keputusan itu.

Iya is a polite, full form meaning yes. It often sounds a little more complete or careful than ya.

• iya = yes
• ya = yes / okay / a softer conversational response

In speech, ya is very common and natural. Iya can sound slightly more deliberate or polite.

So:

• Iya, saya setuju dengan keputusan itu. = Yes, I agree with that decision.
• Ya, saya setuju dengan keputusan itu. means basically the same thing in many situations.

Saya means I and is the standard, polite first-person pronoun.

It can often be omitted in Indonesian if the subject is clear from context. So all of these are possible:

• Saya setuju dengan keputusan itu.
• Setuju dengan keputusan itu.

The version with saya is clearer and slightly more complete. Learners often see pronouns omitted in natural conversation, but including saya is perfectly good and often safer.

Setuju means to agree or in agreement. In Indonesian, words do not always fit neatly into English-style categories. In practice, setuju behaves like a predicate word that can mean:

• agree
• be in agreement

So:

• Saya setuju. = I agree.
• literally, it can feel like I am agreeable / in agreement, but in normal English translation it is just I agree.

You do not need a separate word for am in this sentence.

Dengan usually means with, but after setuju it marks what you agree with.

So:

• setuju dengan sesuatu = agree with something
• setuju dengan seseorang = agree with someone

Examples:

• Saya setuju dengan Anda. = I agree with you.
• Saya setuju dengan usulan itu. = I agree with that proposal.

In this sentence, dengan keputusan itu means with that decision.

The most common and safest choice is setuju dengan.

• setuju dengan = the standard pattern for agree with

You may sometimes see setuju pada in some contexts, especially in more formal or abstract usage, but for learners, setuju dengan is the most natural and reliable form.

Kepada is generally used for to/toward a person, so it would not normally be used after setuju in this sentence.

Keputusan means decision.

It comes from the root putus, which has meanings related to being decided, broken off, or concluded depending on context. The noun keputusan is formed with the circumfix ke-...-an, which often creates abstract nouns.

So:

• putus = decide / be decided / break off, depending on context
• keputusan = decision

This is a useful pattern in Indonesian, though it does not work the same way for every root.

Yes, itu means that, but in Indonesian demonstratives usually come after the noun.

So:

• keputusan itu = that decision
• literally: decision that

This is normal Indonesian word order.

Compare:

• rumah itu = that house
• orang itu = that person
• buku itu = that book

Likewise, this is usually ini after the noun:

• keputusan ini = this decision

Yes, depending on context, itu can sometimes sound closer to the in natural English translation, especially when referring to something already known in the conversation.

For example:

• Saya setuju dengan keputusan itu.

This could be translated as:

• I agree with that decision.
• I agree with the decision.

The exact English choice depends on context. But grammatically, itu is still the demonstrative that.

It is neutral to polite and very natural.

Why?

• iya is polite and common
• saya is the standard polite word for I
• setuju dengan keputusan itu is normal standard Indonesian

In casual speech, a speaker might say:

• Ya, aku setuju sama keputusan itu.

That sounds more informal because:

• aku is less formal than saya
• sama is a common informal substitute for dengan

So the original sentence is a good standard version for learners.

Yes, in everyday spoken Indonesian, many people say sama instead of dengan.

So you may hear:

• Saya setuju sama keputusan itu.
• Aku setuju sama keputusan itu.

This is very common in conversation. However:

• dengan = more standard / more formal / good in writing
• sama = more informal / conversational

For learners, it is useful to know both, but dengan is the safer standard choice.

No. Iya is optional here.

Compare:

• Iya, saya setuju dengan keputusan itu. = Yes, I agree with that decision.
• Saya setuju dengan keputusan itu. = I agree with that decision.

Adding iya makes it sound like you are responding directly to someone, confirming what was said, or answering a yes/no-type prompt. Without iya, it is just a statement.

Yes.

• Iya means yes
• benar means correct / true

So:

• Iya, saya setuju... = Yes, I agree...
• Benar, saya setuju... = That’s correct, I agree...

Benar sounds more like confirming that something is factually correct. Iya is the normal response word for yes. In most everyday situations, iya is the more natural choice here.