riyuu wo kiite mo, watasi ha mada nattokusite imasen.

Here, 聞いても is the grammar pattern verb in て-form + も, which often means even if..., even though..., or even after... depending on context.

So:

• 理由を聞いても = even after hearing the reason
• or more literally, even though I heard the reason

In this sentence, that is the most natural interpretation. It shows that hearing the reason did not change the speaker’s mind.

Because 〜ても is a set grammar pattern, and it always attaches to the て-form of a verb.

So:

• 聞く → dictionary form
• 聞いて → て-form
• 聞いても → even if/though after hearing

You cannot say 聞いたも for this grammar.

聞く can mean both hear/listen and ask, so learners often wonder about that.

In this sentence, 理由を聞いても most naturally means:

• even after hearing the reason
• or even after listening to the explanation

It is theoretically possible for 理由を聞く to mean ask the reason, but with the second half of the sentence—私はまだ納得していません—the meaning hear/listen to the reason fits much better.

So the full sense is: Even after hearing the reason, I’m still not convinced.

Because 理由 is the direct object of 聞く.

• 理由 = reason
• を聞く = hear/ask something

So:

• 理由を聞く = hear the reason / ask the reason

The particle を marks the thing being heard or asked about.

With a negative verb, まだ usually means still or not yet.

So:

• まだ納得していません = I’m still not convinced
• or I have not yet been convinced

This shows that the speaker expected that hearing the reason might lead to understanding or acceptance, but that has not happened yet.

納得する means to be convinced, to be satisfied, or to accept something as understandable/reasonable.

It is stronger than simply understand. A person may understand the explanation logically but still not 納得 emotionally or personally.

So:

• 分かる = understand
• 納得する = be convinced / accept it as satisfactory

In this sentence, 納得していません means the speaker has heard the reason, but still does not feel satisfied or persuaded by it.

This is a very common question.

納得していません uses 〜ている, which often describes a current state in Japanese.

So:

• 納得していません = I am not in a convinced state
• very natural for I’m still not convinced

By contrast, 納得しません sounds more like:

• I do not/will not accept it
• a more direct choice, habit, or refusal

For this sentence, 納得していません is the natural way to describe the speaker’s present condition after hearing the reason.

Yes, it could absolutely be omitted if the subject is already clear from context.

Japanese often leaves out subjects when they are understood. So a very natural version would be:

• 理由を聞いても、まだ納得していません。

Adding 私は does one of these things:

1. makes the subject explicit
2. adds a slight contrast, like as for me
3. emphasizes that I, personally, am still not convinced

So 私は is not wrong or unnatural, but it is not always necessary.

は marks 私 as the topic.

So 私は is not just I; it is more like:

• as for me
• speaking for myself

In this sentence, は can add a subtle contrast:

• maybe someone else accepted the explanation,
• but I, at least, still have not.

That contrast may be very slight, but it is often there.

It is polite because it uses 〜いません.

• 納得していません = polite
• 納得していない = casual/plain

So the plain-style version would be:

• 理由を聞いても、私はまだ納得していない。

The meaning is the same; the difference is politeness and tone.

Yes. That is a very natural translation.

Japanese words do not always match one English word exactly:

• 理由 can be reason
• but depending on context, English may prefer explanation
• 納得していません can be not convinced, not satisfied, or not persuaded

So possible translations include:

• Even after hearing the reason, I’m still not convinced.
• Even after hearing the explanation, I’m still not satisfied.
• Although I heard the reason, I still don’t accept it.

The best English choice depends on the situation.