This is the single most consequential possessive distinction in Danish, and English gives learners no instinct for it. Danish splits "his/her/their" into two systems depending on who owns the thing. The reflexive possessive — sin, sit, sine — means the owner is the subject of the same clause: his/her/their own. The ordinary possessives — hans, hendes, dens, dets, deres — mean the owner is someone else. Choosing wrong does not just sound foreign; it tells your listener a different fact about the world.
The core rule
In a clause with a third-person subject, ask: does the possessor equal the subject?
- Yes → use sin / sit / sine (the subject's own).
- No → use hans / hendes / dens / dets / deres (somebody else's).
Han tager sin bil.
He takes his (own) car.
Han tager hans bil.
He takes his car — meaning another man's car.
Both sentences are perfectly grammatical. They simply describe different events: in the first, the man drives off in his own car; in the second, he takes a different man's car. There is no context in which they are interchangeable. This is why the distinction is a meaning switch, not a register or politeness choice.
sin agrees with the thing owned, not the owner
Unlike English "his/her" (which agree with the owner's sex), Danish sin agrees with the gender and number of the possessed noun — exactly like the indefinite article system. The owner's identity is irrelevant to the form.
| Form | Used with | Example |
|---|---|---|
| sin | common-gender (en-words), singular | sin bil (his/her own car) |
| sit | neuter (et-words), singular | sit hus (his/her own house) |
| sine | plural, both genders | sine børn (his/her own children) |
Hun elsker sit arbejde, men hun savner sine kolleger.
She loves her job but misses her colleagues.
Drengen pakkede sine ting og forlod sit værelse.
The boy packed his things and left his room.
So whether the subject is han, hun, or a name, the choice between sin/sit/sine depends only on the noun: sin for an en-word, sit for an et-word, sine for a plural. (This agreement is laid out further in determiners/possessive-determiners.)
sin can never appear in the subject itself
A hard structural rule: sin/sit/sine must point back to a subject, so it can never be part of the subject. A sentence cannot begin with sin. When the possessor is the subject of the sentence (the thing owned is in the subject position), you must use hans/hendes/deres.
❌ Sin bil er ny.
Impossible — sin cannot stand in the subject.
✅ Hans bil er ny.
His car is new.
The reason is logical, not arbitrary: sin means "belonging to the subject," and here the car is the subject — there is no separate subject for it to refer back to. The same applies inside any subject noun phrase:
Hendes søster bor i Aarhus.
Her sister lives in Aarhus.
Here hendes is required because hendes søster is the subject; sin søster would be ungrammatical at the start of the clause.
Plural subjects: deres, not sin
When the subject is plural (de, or a plural noun), the reflexive possessive for "their own" is deres — the same word as the non-reflexive "their." Danish has no plural reflexive possessive form; sin/sit/sine are singular-subject only.
De solgte deres hus og flyttede til Spanien.
They sold their (own) house and moved to Spain.
❌ De solgte sit hus.
Incorrect — sit cannot take a plural subject.
This collapses a distinction that exists in the singular: with a plural subject you cannot tell from the pronoun alone whether deres hus means "their own house" or "someone else's house." Context resolves it. Only with singular third-person subjects does Danish force the sin / hans contrast.
The tricky case: infinitives and subordinate clauses
The reference point for sin is the subject of its own clause, which is usually obvious. But in infinitive constructions, the controlling subject is the one understood to perform the infinitive's action.
Han bad hende om at hente sin frakke.
He asked her to fetch her (own) coat — the coat belongs to the one fetching: her.
Here sin refers to hende, the understood subject of hente, so the coat is hers. Swap to hans and it becomes his coat:
Han bad hende om at hente hans frakke.
He asked her to fetch his coat — the coat belongs to him.
This is genuinely subtle, and even native speakers sometimes produce ambiguity here, but the underlying rule holds: sin tracks the nearest subject (including the implied subject of an infinitive); hans/hendes tracks anyone else.
Why English speakers get this wrong
English has no reflexive possessive at all. "He loves his wife" uses the same "his" whether the wife is his own or another man's — English leans on context entirely. So the English instinct is to translate "his" as hans every time, which in Danish actively asserts that the thing belongs to someone else. The result is sentences that are grammatical but say something the speaker never meant.
Han elsker sin kone.
He loves his (own) wife.
Han elsker hans kone.
He loves his wife — i.e. some other man's wife.
The second sentence is the one English speakers produce by accident, and to a Dane it unambiguously means he is in love with another man's wife. This is the comprehension consequence to burn in: hans where you meant sin does not read as a small slip — it changes who owns the noun. (More transfer cases at mistakes/sin-hans-owner.)
Common Mistakes
❌ Hun ringede til hendes mor.
Incorrect if she rang her own mother — implies someone else's mother.
✅ Hun ringede til sin mor.
She called her (own) mother.
❌ Peter glemte hans nøgler i bilen.
Incorrect if they're Peter's keys — hans points to another man.
✅ Peter glemte sine nøgler i bilen.
Peter forgot his (own) keys in the car.
❌ De inviterede sit hele familie.
Incorrect — plural subject can't take sit; and word order/agreement is off.
✅ De inviterede hele deres familie.
They invited their whole family.
❌ Sin telefon lå på bordet.
Impossible — sin cannot stand in the subject.
✅ Hans telefon lå på bordet.
His phone was on the table.
❌ Barnet legede med hans bamse.
Incorrect if it's the child's own teddy — hans points elsewhere.
✅ Barnet legede med sin bamse.
The child played with its (own) teddy bear.
Key Takeaways
- Same owner as the subject → sin/sit/sine. Different owner → hans/hendes/dens/dets/deres. It is a fact-changing choice, not stylistic.
- sin/sit/sine agree with the possessed noun (en-word → sin, et-word → sit, plural → sine), never with the owner's sex.
- sin can never sit in the subject of the clause; use hans/hendes there.
- Plural subjects always use deres — there is no plural sin.
- The default English instinct (translate "his" as hans) systematically produces the "someone else's" reading. Train yourself to ask "his own?" before every third-person possessive.
Now practice Danish
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- Possessive Agreement in DepthB1 — Which Danish possessives inflect with the possessed noun (min/mit/mine) and which never change (hans/hendes/deres) — one table that fixes most errors.
- Using Hans/Hendes Instead of SinB1 — Why Danish uses the reflexive possessive sin/sit/sine for self-owned things, and how hans/hendes/deres silently change who the owner is.