tokumeihaisou ha anzenna ippou de, tyakubarai ha takai.

• 匿名配送 means anonymous shipping/delivery. It is commonly used on Japanese online marketplace apps and services, where the buyer and seller do not directly see each other’s personal information such as full name or address.
• 着払い means the recipient pays the shipping cost when the package arrives.

A very important point:

• 着払い is not exactly the same as 代引き.
• 着払い = the receiver pays the shipping fee
• 代引き = the receiver pays the item price on delivery (cash on delivery in the usual sense)

So if you learned 着払い as cash on delivery, be careful: that English gloss can be misleading.

一方で means something like:

• while
• whereas
• on the other hand

It is used to present a contrast between two statements.

So the structure here is:

• 匿名配送は安全な一方で、着払いは高い。

This sets up two contrasting points:

• anonymous delivery has the advantage of being safe
• cash-on-arrival shipping has the disadvantage of being expensive

It does not have to mean complete opposition. It often just means these are two different contrasting aspects.

Because 安全 is a na-adjective.

When a na-adjective comes before a noun-like expression, it takes な. In this pattern, 一方 behaves like a noun, so you get:

• 安全な一方で

Compare:

• 静かな人
• 便利な方法
• 安全な一方で

So this is the normal grammar for a na-adjective before 一方で.

By contrast, 安全で is the te-form of 安全だ, and that would be used in a different structure, such as:

• 匿名配送は安全で、便利です。

That means anonymous delivery is safe and convenient, not the same contrast pattern as 一方で.

Here, は marks the topic, and it also creates a contrastive feeling.

So:

• 匿名配送は = as for anonymous delivery
• 着払いは = as for collect-on-delivery shipping

Using は in both parts helps the sentence feel like a comparison of two options or two features.

If you used が instead, the nuance would change. が would focus more on the subject itself, while は here is better for setting up a contrast between the two shipping methods.

For learners, it is best to think of 一方で as a set expression meaning while / on the other hand.

You may also see:

• 一方
• 一方で
• 一方では

All of these can show contrast, but 一方で is a very common form.

So in practice, memorize:

• A は / が ... 一方で、B は / が ...

as one useful contrast pattern.

Here it means expensive or costly.

高い can mean:

• physically high
• expensive

The meaning depends on context.

Since the sentence is about shipping/payment methods, 着払いは高い means:

• collect-on-delivery shipping is expensive
• the cost is high

It is not talking about physical height.

Not directly.

The sentence does not say:

• 匿名配送 is safer than 着払い

Instead, it contrasts different qualities:

• 匿名配送 → safe
• 着払い → expensive

So the speaker is not necessarily claiming that 着払い is unsafe. They are just presenting a different negative point about it.

In other words, the sentence is more like:

• Anonymous delivery has the advantage of safety, whereas collect-on-delivery is costly.

Yes, in many situations you could replace it, but the nuance changes.

For example:

• 匿名配送は安全だけど、着払いは高い。

This is more conversational and straightforward: safe, but expensive.

Using 一方で sounds:

• a bit more formal
• more balanced
• more like written explanation or comparison

So:

• けど = casual, everyday contrast
• 一方で = more structured, explanatory contrast

The comma simply helps separate the two contrasting parts of the sentence:

• 匿名配送は安全な一方で、
• 着払いは高い。

It makes the sentence easier to read.

Japanese punctuation is somewhat flexible, so the comma is helpful but not always absolutely required. In a sentence like this, though, it is very natural to include it.

Yes, it is grammatical and natural.

It has a slightly explanatory or written feel because of 一方で, so it sounds like something you might see in:

• a product description
• an online marketplace explanation
• a comparison of shipping options

A more casual spoken version would be:

• 匿名配送は安全だけど、着払いは高い。

Both are natural; the original just sounds a little more formal or analytical.