naruhodo, kono madori nara hutari de sunde mo amari semaku nasasou da.

なるほど is a reaction word meaning something like I see, I get it, or that makes sense.

It often appears when the speaker has just understood something or is evaluating new information. In this sentence, it sounds like the speaker is looking at the floor plan and thinking:

Ah, I see. In that case...

It does not add core grammar to the sentence; it mainly shows the speaker’s reaction.

間取り（まどり） means a floor plan, layout, or room arrangement of a home or apartment.

So この間取り means this floor plan or this layout.

There is no particle between この and 間取り because この directly modifies the noun, just like this in English:

• この本 = this book
• この部屋 = this room
• この間取り = this floor plan

Here, なら means something like:

• if it’s this floor plan
• given this floor plan
• as for this layout

It sets up the condition or basis for the judgment that follows.

So この間取りなら means the speaker is saying: If we're talking about this particular layout, then...

This なら often has the nuance of making a judgment based on the topic just mentioned or just observed.

In 二人で住む, the particle で shows the group involved in doing the action together.

So 二人で住む means: to live together as two people or for two people to live there

This use of で is common with numbers of people:

• 一人で行く = go alone
• 三人で食べる = three people eat together
• 二人で住む = two people live together

If you said 二人が住む, it would focus more on two people as the grammatical subject. That is possible in some contexts, but 二人で住む is the more natural way to say live there as two people / live together as a pair.

住んでも is 住んで + も, from the verb 住む.

The pattern て + も often means:

• even if ...
• even when ...
• even with ... doing ...

So 二人で住んでも means: even if two people live there or more naturally in this sentence: even with two people living there

The point is that the speaker is evaluating the space under that condition.

It is the same particle も, but here it is part of the grammar pattern ても, which has a different function.

Compare:

• 私も行く = I will go too
• 行ってもいい = it’s okay to go
• 住んでも狭くなさそう = even if people live there, it doesn’t seem cramped

So in this sentence, も is not simply also. It helps form the conditional meaning even if / even when.

あまり is commonly used with a negative expression to mean:

• not very
• not much
• not particularly

So:

• あまり狭くない = not very cramped
• あまり高くない = not very expensive
• あまり好きじゃない = don’t like it very much

In your sentence, the negative idea is inside 狭くなさそう (doesn’t seem narrow/cramped), so あまり means:

doesn’t seem very cramped

A positive sentence like あまり狭い would sound unnatural.

狭くなさそう means doesn’t seem narrow/cramped.

It comes from the negative form of the adjective 狭い:

• 狭い = narrow, cramped
• 狭くない = not narrow, not cramped

Then that negative expression is combined with そう (seems), giving:

• 狭くなさそう = seems not cramped

A useful pattern is:

• i-adjective → 〜くなさそう
• 高い → 高くなさそう = doesn’t seem expensive
• 難しい → 難しくなさそう = doesn’t seem difficult

So 狭くなさそう is a very natural way to say it doesn’t look very cramped.

This is not the hearsay そうだ.

Japanese has two common そうだ patterns:

1. Hearsay そうだ = I hear that... / they say that...

   • 雨が降るそうだ = I hear it will rain

2. Appearance/seeming そうだ = looks... / seems...

   • おいしそうだ = looks delicious
   • 狭くなさそうだ = doesn’t seem cramped

In your sentence, it is the second one: appearance/judgment.
The speaker is judging based on what they see or think, not reporting what someone else said.

The final だ makes the sentence a plain-style statement.

So:

• 狭くなさそうだ = it seems not cramped
• 狭くなさそうです = it seems not cramped (polite)

In casual speech, the だ is sometimes omitted:

• 狭くなさそう But in written or spoken plain style, だ is very common.

A helpful breakdown is:

• なるほど、 = I see...
• この間取りなら = if it’s this floor plan / given this layout
• 二人で住んでも = even if two people live there
• あまり狭くなさそうだ = it doesn’t seem very cramped

So the logic is:

I see. Given this layout, even if two people live there, it doesn’t seem very cramped.

The sentence is making a judgment based on the layout.

Literally, 狭い means narrow. But with homes, rooms, apartments, and living space, it often means:

• small
• cramped
• tight

So in this sentence, 狭くなさそう is more naturally understood as: doesn’t seem too cramped rather than only doesn’t seem narrow.

That is a very common nuance when talking about housing.

Japanese often leaves out subjects and other information when they are obvious from context.

Here, the thing being judged is understood from この間取り: the apartment/room/place with this floor plan.

So instead of saying something like: This apartment doesn’t seem very cramped Japanese just says: この間取りなら…狭くなさそうだ

This is very normal Japanese. The listener is expected to understand what is being talked about from context.