sore ha honno rei desu.

Normally, it is written without spaces:

それはほんの例です。

The spaces here are just for learners, to make the parts easier to see.

It is read:

sore wa honno rei desu

A couple of notes:

• は is written ha, but here it is pronounced wa because it is the topic particle.
• 例 is read れい (rei).

それ means that.

It usually refers to:

• something near the listener,
• or something already mentioned in the conversation.

So in this sentence, それ is the thing being talked about: that is just an example.

は marks the topic of the sentence.

So それは means something like:

• as for that
• or more naturally in English, just that

Japanese often organizes sentences as topic + comment. Here:

• それは = as for that
• ほんの例です = it is just an example

When は is used as a particle, it is pronounced wa.

So:

• は as a normal syllable: ha
• は as the topic particle: wa

This is one of the first pronunciation exceptions learners meet.

ほんの means just, mere, or only in front of a noun.

So ほんの例 means:

• just an example
• only an example
• a mere example

It adds the nuance that the thing should not be taken as the whole story or something very important.

Because ほんの directly modifies the noun 例.

In Japanese, some words go straight before a noun, like adjectives or determiner-like words. So:

• ほんの例 = just an example

You do not need another particle there.

Also, even though ほんの ends in の, here it is best understood as part of the expression ほんの, not as a separate possessive of-type の.

例 means example.

It is read れい (rei).

So:

• ほんの例 = just an example

Japanese does not use articles like a, an, and the the way English does.

So 例 can mean:

• an example
• the example
• just example

The exact meaning depends on context. In this sentence, English naturally uses an example.

です makes the sentence polite and works like is in this kind of sentence.

So:

• それはほんの例です。 = polite: That is just an example.
• それはほんの例だ。 = plain/casual
• それはほんの例。 = very casual, often in speech

So です is a very common polite sentence ending.

Yes. それは例です means That is an example.

Adding ほんの changes the nuance:

• それは例です = That is an example.
• それはほんの例です = That is just an example.

So ほんの makes it softer and more limiting, as if the speaker is saying, Don't read too much into it; it's only an example.

Using は makes それ the topic: as for that, it is just an example.

This is very natural when:

• the thing is already known,
• already visible,
• or already mentioned.

If you used が, it would sound more like identifying or emphasizing the subject. In many situations, は is the more natural choice for a simple statement like this.

Yes, it is completely natural.

それはほんの例です。 is a normal, polite way to say:

• That’s just an example.

It would fit well in explanations, lessons, discussions, or anytime someone wants to say that something should not be taken as a complete or final case.