אני לא רוצה לקנא בה; אני שמחה בשבילה.

A natural pronunciation is:

Ani lo rotzah lekané bah; ani smechah bishvilah.

A few notes:

• רוצה = rotzah if the speaker is female
• לקנא = lekané
• בה = bah
• שמחה = smechah if the speaker is female
• בשבילה = bishvilah

If a male speaker says it, you would hear rotzeh and sameach instead.

Because the speaker is female.

In Hebrew, adjectives and many present-tense verb forms agree with the gender of the speaker or subject.

So here:

• אני לא רוצה = I do not want said by a woman
• אני שמחה = I am happy said by a woman

If a man were speaking, it would be:

• אני לא רוצה לקנא בה; אני שמח בשבילה.

Notice the changes:

• רוצה stays spelled the same, but for a male it is usually pronounced rotzeh
• שמחה changes to שמח

Because the verb לקנא works with the preposition ב־ in Hebrew.

So Hebrew says, literally, something like:

• לקנא ב... = to be jealous of ... / to envy ...

That is just the pattern this verb takes. It does not usually take a direct object the way English envy does.

Examples:

• אני מקנא בו = I’m jealous of him
• היא מקנאה בה = She’s jealous of her
• אנחנו מקנאים בהם = We’re jealous of them

So בה is not random; it is the pronoun form used after the preposition ב־.

בה means in her / her after the preposition ב־.

In this sentence, because לקנא requires ב־, בה means of her / her in the sense required by the verb:

• לקנא בה = to be jealous of her

It is the combination of:

• ב־ = in / at / with / of, depending on the verb
• ה = her

In modern pronunciation, בה here is usually bah.

They both refer to her, but they do very different jobs.

• בה is used because the verb לקנא requires ב־

  • לקנא בה = to be jealous of her

• בשבילה means for her

  • אני שמחה בשבילה = I’m happy for her

So:

• בה is tied to the grammar of לקנא
• בשבילה expresses for her sake / on her behalf / for her

They are not interchangeable.

Both are possible, but they mean slightly different things.

• אני לא רוצה לקנא בה = I don’t want to be jealous of her
  This focuses on the speaker’s desire or intention.

• אני לא מקנאה בה = I’m not jealous of her
  This simply states a current fact.

So the sentence you gave is a little more nuanced. It suggests something like:
I don’t want to feel jealousy; instead, I’m happy for her.

That contrast fits very well with the second part, אני שמחה בשבילה.

בשבילה is built from בשביל plus the pronoun her.

• בשביל = for
• בשבילה = for her

Other examples:

• בשבילי = for me
• בשבילך = for you
• בשבילו = for him
• בשבילנו = for us

In everyday Hebrew, בשביל is a very common way to say for.

So:

• אני שמחה בשבילה = I’m happy for her

Usually not if you want the same meaning.

אני שמחה בשבילה means I’m happy for her, in the sense of being glad on her behalf.

If you used לה, it would sound like a different structure and usually would not express this idea naturally.

Hebrew commonly says:

• שמח/שמחה בשביל מישהו = happy for someone

So בשבילה is the natural choice here.

Not always, but repeating it is very normal and clear.

Your sentence has:

• אני לא רוצה לקנא בה; אני שמחה בשבילה.

This is fully natural and balanced.

In casual speech, especially when the subject is obvious, Hebrew sometimes drops the pronoun:

• לא רוצה לקנא בה, שמחה בשבילה.

That can sound conversational, especially if a woman is speaking and the context is clear. But for learners, repeating אני is safer and clearer.

Yes. The semicolon works well because the sentence has two closely connected parts:

• אני לא רוצה לקנא בה
• אני שמחה בשבילה

The semicolon shows a strong connection and contrast between them.

That said, in everyday writing many people would also use:

• a comma: אני לא רוצה לקנא בה, אני שמחה בשבילה.
• or a full stop: אני לא רוצה לקנא בה. אני שמחה בשבילה.

All of these can be natural depending on style.

It would be:

אני לא רוצה לקנא בה; אני שמח בשבילה.

The important change is:

• שמחה → שמח

Also, רוצה is written the same way, but a male speaker usually pronounces it rotzeh, while a female speaker usually pronounces it rotzah.

So:

• female speaker: אני לא רוצה לקנא בה; אני שמחה בשבילה
• male speaker: אני לא רוצה לקנא בה; אני שמח בשבילה