asita no siken no kekka ga ki ni natte, konya ha amari nemuremasen.

Each の links one noun to another.

• 明日の試験 = tomorrow's exam / the exam tomorrow
• 試験の結果 = the exam's results / the results of the exam

So:

• 明日の試験の結果 = the results of tomorrow's exam

Japanese often stacks nouns this way, and の is the standard particle for connecting them.

It means tomorrow's exam, or more naturally in English, the exam tomorrow.

In Japanese, 明日 can modify a noun with の:

• 明日の予定 = tomorrow's plans
• 明日の会議 = tomorrow's meeting
• 明日の試験 = tomorrow's exam

So even though the English phrasing may sound a little different depending on context, the Japanese is completely natural.

気になる is a very common expression meaning things like:

• to be on one's mind
• to worry about
• to be curious about
• to be concerned about

Literally, it is something like to become a matter of one's mind/attention, but you usually should not translate it word-for-word.

In this sentence:

• 結果が気になる = I'm worried about the results / The results are on my mind

So the idea is not just simple curiosity. It often carries a feeling of mental preoccupation.

Both are related, but they are not used in exactly the same way.

• 結果が気になる = the results are bothering me / on my mind
• 結果を気にする = I worry about the results / I pay too much attention to the results

A useful way to think about it:

• 気になる focuses more on the feeling arising naturally
• 気にする focuses more on the person's act or tendency of worrying

In this sentence, 結果が気になって sounds very natural because it describes the speaker's mental state leading to not being able to sleep.

Because 気になる typically takes が for the thing that is bothering you or occupying your mind.

So:

• 結果が気になる
• 将来が気になる
• 彼の反応が気になる

This is different from verbs that take を. Since 気になる behaves like a set expression, it is best to learn it as X が 気になる.

なって is the て-form of なる inside the expression 気になる.

So:

• dictionary form: 気になる
• て-form: 気になって

Here, the て-form connects to the next clause and gives a reason or background:

• 気になって、今夜はあまり眠れません
• Because it's on my mind, I can't sleep much tonight

So 気になって is functioning a bit like because I'm worried about it.

は marks 今夜 as the topic or contrastive topic.

• 今夜は = as for tonight / tonight, at least

It gives a natural sense of setting the scene:

• Tonight, I can't sleep much

Using は here can also suggest contrast, even if only slightly:

• maybe not every night
• but tonight, because of this, I can't sleep much

So 今夜は sounds very natural in context.

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

• not very
• not much
• not really

So:

• あまり眠れません = can't sleep much / don't sleep very well

This is a very standard pattern:

• あまり食べません = I don't eat much
• あまり分かりません = I don't understand very well
• あまり好きじゃない = I don't like it very much

You normally expect a negative form after あまり in this usage.

This is an important nuance.

• 寝ません = I do not go to bed / I do not sleep as a choice or action
• 眠れません = I cannot sleep / I am unable to fall asleep

Here the speaker is not choosing to stay awake. They are unable to sleep because they are worried. So 眠れません is the better choice.

Also, 眠れる is the potential form of 眠る, so 眠れません expresses inability very naturally.

Because the whole sentence is in polite style.

• plain form: 眠れない
• polite form: 眠れません

Japanese speakers choose either plain style or polite style depending on situation, audience, and tone. This sentence is simply written in polite style, which is common in textbooks and general conversation.

A plain-style version would be:

• 明日の試験の結果が気になって、今夜はあまり眠れない。

Yes, the subject is omitted, and it is understood from context to be I.

Japanese very often leaves out subjects when they are obvious. So this sentence naturally means:

• I can't sleep much tonight because I'm worried about the results of tomorrow's exam.

You do not need to say 私は unless there is a reason to emphasize or contrast it.

Not exactly.

• あまり眠れません = can't sleep much / can't sleep very well
• 全然眠れません = can't sleep at all

So あまり leaves room for a little sleep, but not much. It sounds softer than 全然.

The comma helps readability, but it is not grammatically essential.

It separates:

• the reason/background: 明日の試験の結果が気になって
• the main statement: 今夜はあまり眠れません

Japanese punctuation is often more flexible than English punctuation, so you may see the same sentence written without a comma. The meaning does not change.