Learn Hardcore Japanese: zitu ha kanozyo ha gokai wo site ita.

実は is a sentence opener that frames what follows as new, possibly surprising, or contrary to what the listener might think. In English it’s like “actually,” “to tell you the truth,” or “as it turns out.” It often softens revelations or corrections.

Why are there two は’s (実は and 彼女は)? Are they the same は?

Yes, it’s the same particle は (pronounced “wa”). In 実は, it forms a fixed adverbial expression meaning “actually.” The second は after 彼女 is the topic marker, setting “she” as the topic of the sentence. They can co-exist without issue.

Why is は pronounced “wa” here?

The topic particle is written は but pronounced “wa” due to historical spelling. So both 実は and 彼女は are read with “wa.”

Why use 誤解をしていた instead of 誤解した?

誤解をしていた (the ている past) presents a state that obtained at that time: “she was (in a state of) misunderstanding / she had things wrong.”
誤解した is a simple completed action: “she misunderstood (at some point).”
When the nuance is “she was mistaken” or “had misunderstood (and was still under that impression),” していた is more natural.

What exactly does していた contribute here?

〜している can express:

ongoing action (progressive),
habitual action, or
a resulting state.

With 誤解, it’s the resulting state: “to be under a misunderstanding.” The past していた means she was in that state at some reference time (“she was mistaken” / “she had misunderstood”).

Is 誤解をする different from 誤解する? Do I need the を?

Both are standard:

誤解する
誤解をする

They mean the same. Many speakers prefer the shorter 誤解する, but 誤解をする is also common and sometimes feels a touch more formal or explicit. In the ている form, both 誤解していた and 誤解をしていた are fine.

Is 誤解 a noun or a verb?

誤解 is a noun meaning “misunderstanding.” Combined with する it becomes a verb (“to misunderstand”). This type is called a する-verb or verbal noun.

How does 彼女 work here? Could it also mean “girlfriend,” and can it be omitted?

彼女 can mean “she” or, in the right context, “girlfriend.” Without context, read it as “she.” Japanese often omits pronouns, so 実は誤解していた。 would be very natural if “she” is inferable from context.

What’s the difference between 彼女は and 彼女が here?

彼女は marks “she” as the topic; it’s neutral and common once “she” is established in the discourse.
彼女が marks “she” as the grammatical subject and often highlights or contrasts her: 実は、彼女が誤解していた。 = “Actually, it was she who misunderstood (not someone else).”

Where does 実は normally go, and should there be a comma?

実は typically appears at the start: 実は、… A comma after it is common in writing. You can also place it after the topic: 彼女は、実は、誤解していた。 The version at the very front is most frequent.

How do I specify what was misunderstood?

Common patterns:

Object + を: 彼女は彼の意図を誤解していた。 (She misunderstood his intention.)
Clause + と/という: 彼女は彼が怒っていると誤解していた。 / …という誤解をしていた。
Noun phrase + という誤解: 彼は既婚だという誤解をしていた。

What’s the difference between 誤解 and 勘違い?

誤解: “misunderstanding,” often about misinterpreting someone/something; neutral and common in writing and speech.
勘違い: “mistaken idea/mix-up,” more casual/colloquial; often about one’s own mistaken assumption.
In many everyday contexts they overlap: 勘違いしていた ≈ “I was mistaken.”

How do I make this polite, negative, or both?

Polite: 実は、彼女は誤解していました。
Negative (plain): 実は、彼女は誤解していなかった。
Negative (polite): 実は、彼女は誤解していませんでした。 For honorific nuance (subject is someone you respect): 誤解なさっていました。

Could I say 誤解してた (without い) in speech?

Yes. していた → してた is a common casual contraction in speech: 実は、彼女は誤解してた。 Avoid it in formal writing.

Why does している use いる (and thus いた), not ある?

In the 〜ている construction, いる is the auxiliary that marks ongoing/resulting states for verbs. Its past is いた. This いる is not the existence verb contrasting with ある; it’s a grammatical auxiliary, and you don’t swap it for ある in this pattern.

Is there anything off about the spacing in the given sentence?

Yes. Standard Japanese writing doesn’t put spaces between words. A natural written form is: 実は、彼女は誤解をしていた。 The spaces were likely added for learners.

How would I read/pronounce the whole sentence?

Romanization: Jitsu wa, kanojo wa gokai o shite ita.
Kana: じつは、かのじょはごかいをしていた。
Remember particle は is pronounced “wa.”

Can I add んだ for an explanatory tone?

Yes. 実は、彼女は誤解していたんだ。 (plain, explanatory/softening) or …んです。 (polite). This adds an “as it turns out / you see” flavor and is very natural in conversation.