i sinbareun onraineseo pumjeorieossneunde geuncheo maejangeneun jaegoga issdae.

은/는 marks the topic of the sentence, while 이/가 usually marks the subject more directly.

Here, 이 신발은 means something like as for these shoes. The speaker is introducing the shoes as the topic and then saying two things about them:

• online they were sold out
• but a nearby store has stock

So 이 신발은 sounds very natural because the whole sentence is about these shoes as a topic.

If you said 이 신발이, it would feel more like you are specifically identifying these shoes as the subject in contrast to something else, which is less natural in this context.

온라인에서 means online or more literally in the online store / on the internet.

The particle 에서 is commonly used for the place where something happens or applies. In this sentence, it marks the location/context where the shoes were sold out:

• 온라인에서 품절이었는데 = they were sold out online

Even though online is not a physical place, Korean often treats it like a location in this kind of expression.

You may also hear:

• 온라인에서는 — with extra contrast/topic nuance
• 온라인에 — less natural for this exact meaning

So in this sentence, 에서 is the most natural choice.

It breaks down like this:

• 품절 = sold out
• 이다 = to be
• 이었 = past form of 이다
• 는데 = connective ending

So:

• 품절이다 = to be sold out
• 품절이었다 = was sold out
• 품절이었는데 = was sold out, but / was sold out, and...

Because 품절 is a noun, Korean uses 이다 with it.

So this is not a verb meaning sold out by itself; it is more like:

• 품절 = a sold-out status
• 품절이다 = to be in a sold-out state

-는데 often connects two clauses, but its exact meaning depends on context. It can mean:

• but
• and
• so
• while
• background-setting information before the main point

In this sentence, it has a contrastive feeling:

• 온라인에서 품절이었는데 근처 매장에는 재고가 있대.
• It was sold out online, but I heard a nearby store has it in stock.

So but is a good natural translation here.

Still, it is helpful to remember that -는데 is not always a strong, direct but. Sometimes it just sets up the situation before the next statement.

근처 매장에는 = at a nearby store, though / as for nearby stores

This is:

• 근처 매장에 = at a nearby store
• plus 는, which adds contrast or topic emphasis

That contrast is important here:

• 온라인에서는 없었지만
• 근처 매장에는 있다

Even though the sentence does not use exactly those words, that is the feeling: online, it was sold out; but at a nearby store, there is stock.

So 에는 helps highlight the difference between:

• 온라인에서
• 근처 매장에는

If you said just 근처 매장에 재고가 있대, it would still be grammatical, but the contrast would be a little weaker.

Here 재고가 marks stock as the thing that exists.

• 재고가 있다 = there is stock / it is in stock

This is a very common pattern in Korean:

• N이/가 있다 = there is N

So 재고가 있다 is the basic, natural expression for to have stock / to be in stock.

If you said 재고는 있대, that would add contrast, like:

• there is stock, at least
• as for stock, they do have it

That is possible in some contexts, but the neutral form here is 재고가 있대.

No. 있대 is different from 있어요.

있대 comes from an indirect-quotation / hearsay form. It means something like:

• they say there is
• I heard there is
• apparently there is

So:

• 재고가 있어요 = there is stock
• 재고가 있대 = I heard there is stock / they say there is stock

This tells you the speaker is not necessarily stating it as firsthand knowledge. They may have heard it from:

• a website
• an employee
• a friend
• someone else

It is a casual spoken form. A more polite version would be:

• 재고가 있대요

It comes from the quoted form of 있다.

Very roughly:

• 있다고 해 = someone says there is / I heard there is
• in speech, this contracts to 있대

So 재고가 있대 is a shortened spoken form of something like:

• 재고가 있다고 해
• 재고가 있대

This contraction is very common in everyday Korean.

Similar examples:

• 좋대 = I heard it is good
• 비싼데? is different, not the same pattern
• 간대 = I heard they’re going
• 학생이래 = I heard he/she is a student

So 있대 is part of a very common spoken hearsay pattern.

Because they describe different kinds of meanings.

1. 품절이다

품절 is a noun meaning sold-out status. Korean expresses this as:

• 품절이다 = to be sold out

So it behaves like a noun + 이다.

2. 재고가 있다

재고 means stock/inventory. Korean expresses the idea of having stock as:

• 재고가 있다 = stock exists / there is inventory

So it uses the existence verb 있다.

This difference is very common in Korean. Different nouns pair naturally with different structures, and you usually just learn the standard expression:

• 품절이다
• 재고가 있다

Yes, in many situations it could, but there is a slight nuance difference.

• 품절이었는데 = it was sold out
• 품절됐는데 = it became sold out / was sold out

In everyday speech, both can often be translated similarly.

The difference is:

• 품절이다 focuses more on the state
• 품절되다 can feel a little more like become sold out or be marked as sold out

In this sentence, 품절이었는데 sounds very natural because the speaker is simply describing the status online.

Yes. Korean often omits information that is clear from context.

The sentence starts with:

• 이 신발은 = as for these shoes

After that, the rest of the sentence is understood to still be about those shoes. So in the second part, Korean does not need to repeat the shoes.

A more explicitly repeated version would sound something like:

• 이 신발은 온라인에서 품절이었는데 근처 매장에는 이 신발 재고가 있대.

But that repetition sounds unnecessary and less natural. Korean usually leaves it out when the topic is already clear.

Because Korean often does not mark a/the the way English does.

• 근처 = nearby
• 매장 = store, shop

So 근처 매장 could mean:

• a nearby store
• the nearby store
• nearby stores in some contexts

In this sentence, English usually prefers a nearby store or a nearby shop unless the specific store is already known.

This is a common issue for English speakers: Korean nouns usually do not directly tell you whether something is a or the. You figure that out from context.

The sentence does more than just give information. It has a natural contrastive flow:

• online: sold out
• nearby store: still in stock
• 있대: this is based on heard information, not necessarily direct confirmation

So the feeling is something like:

• These shoes were sold out online, but I heard a nearby store has them in stock.

The key grammar points creating that nuance are:

• 이 신발은 → sets the topic
• 품절이었는데 → gives background plus contrast
• 매장에는 → emphasizes the contrast with online
• 있대 → adds hearsay / reported information

That combination makes the sentence sound very natural and conversational.