Hon frågar sin syster vad en bra lön är för jobbet.

Sin/sitt/sina is the reflexive possessive and is used when the possessor is the subject of the clause. Here, the subject is hon (she), and the sister belongs to that same hon, so Swedish prefers sin syster = her (own) sister.
Hennes syster would normally mean someone else’s sister (or it would sound like you’re emphasizing/clarifying whose sister it is).

The form of sin/sitt/sina agrees with the thing owned (the noun after it), not with the owner.

• syster is an en-word → sin syster
• barn (ett-word) → sitt barn
• plural → sina barn

fråga is the infinitive (to ask).
frågar is present tense (asks / is asking). Swedish present tense covers both she asks and she is asking, depending on context.

Swedish typically does not use a comma to introduce an embedded/indirect question clause like vad en bra lön är.... It’s written as one continuous sentence.

Because this is an indirect question (embedded under frågar). In Swedish indirect questions use statement word order (subject before verb):

• Direct question: Vad är en bra lön?
• Indirect question: ... vad en bra lön är ...

Yes. vad introduces the content of what she’s asking: vad en bra lön är... = what a good salary is... It functions like “what” introducing an embedded clause.

Because it’s talking about the concept of a good salary in general for that job, not a specific already-known salary. Swedish often uses the indefinite form for “a good X” in general statements/questions: en bra lön.

lön is an en-word (common gender), so the indefinite article is en and the adjective uses the en form: en bra lön. (If it were an ett-word, you’d get ett bra ....)

för jobbet means for the job (i.e., in exchange for doing that work / for that position).
till jobbet usually means to the job / to work (the place), focusing on direction/destination, so it would be wrong for salary.

jobbet is the definite form: the job. Swedish often attaches -et/-en to the noun instead of using a separate word like “the.”

• ett jobb = a job
• jobbet = the job

They mean different things:

• för jobbet = salary for that job/position (most natural here)
• på jobbet = at work / at the workplace (location/context)
• i jobbet = in the job (often about being in the role; less common in this meaning)

Common points learners notice:

• frågar has the å sound (roughly like the vowel in more in many accents): FRÅ-gar
• syster has a clear y vowel (a front rounded sound that English doesn’t have): SYS-ter
• lön has the Swedish ö vowel (also not in English)
• In vad en bra lön är, the stress tends to fall on content words like bra and lön, while en is usually unstressed.