Jag måste erkänna att jag glömde hennes födelsedag förra veckan.

Because måste refers to the speaker’s situation now: I must admit...

The forgetting happened in the past, so Swedish uses past tense there: glömde.

So the timeline is:

• Jag måste erkänna = I have to admit / I must admit (now)
• att jag glömde hennes födelsedag förra veckan = that I forgot her birthday last week (past event)

This works the same way in English:

• I must admit that I forgot her birthday last week.

After modal verbs like måste, Swedish normally uses the infinitive without the infinitive marker att.

So:

• jag måste erkänna
• jag kan komma
• jag vill gå
• jag ska läsa

Not:

• jag måste att erkänna ❌

This is similar to English, where we say:

• I must admit not
• I must to admit ❌

This att is a different att.

Swedish att can mean two different things:

1. Infinitive marker = to

   • att läsa = to read

2. Subordinating conjunction = that

   • Jag vet att du är här = I know that you are here

In Jag måste erkänna att jag glömde hennes födelsedag förra veckan, the second att means that:

• Jag måste erkänna att... = I must admit that...

So:

• no att after måste
• yes att to introduce the clause jag glömde hennes födelsedag

Glömde is the past tense (preterite) of glömma = to forget.

Main forms:

• infinitive: glömma
• present: glömmer
• past: glömde
• supine: glömt

Since the sentence refers to a finished event in the past, Swedish uses glömde:

• jag glömde hennes födelsedag
• I forgot her birthday

This is a very common Swedish question.

Swedish uses sin / sitt / sina for a reflexive possessor, meaning the possession belongs to the subject of that clause.

Here, the subject of the clause att jag glömde hennes födelsedag is jag.

So:

• sin födelsedag would mean my own birthday (the subject’s own birthday)
• hennes födelsedag means her birthday (someone else’s birthday)

Compare:

• Jag glömde min födelsedag. = I forgot my birthday.
• Hon glömde sin födelsedag. = She forgot her own birthday.
• Hon glömde hennes födelsedag. = She forgot her birthday, but her refers to another woman, not the subject.

So hennes is correct because the birthday belongs to someone other than the subject jag.

Because Swedish normally does not use the suffixed definite article when there is a possessive word like min, din, hans, hennes, vår, deras.

So you say:

• hennes födelsedag = her birthday
• min bok = my book
• deras hus = their house

Not:

• hennes födelsedagen ❌
• min boken ❌

The possessive already makes the noun definite enough.

Because the second part is its own clause, and that clause needs its own subject.

Structure:

• main clause: Jag måste erkänna
• subordinate clause: att jag glömde hennes födelsedag förra veckan

Even though English also repeats the subject here, learners sometimes expect Swedish to drop it. But Swedish normally keeps it:

• Jag tror att jag förstår.
• Hon sa att hon var trött.

So jag must appear again in the att-clause.

Because in a subordinate clause introduced by att, the normal order is subject + verb.

So:

• att jag glömde
• att hon kom
• att vi förstår

This is different from the V2 rule in main clauses, where the finite verb often comes second.

Compare:

• main clause: Jag glömde hennes födelsedag.
• subordinate clause: ... att jag glömde hennes födelsedag.

If you add certain adverbs, you can see the subordinate-clause pattern more clearly:

• Jag vet att jag inte glömde det.

Notice inte comes before the verb in the subordinate clause:

• att jag inte glömde

In Swedish, many time expressions do not need a preposition.

So you say:

• förra veckan = last week
• förra året = last year
• i går = yesterday
• nästa månad = next month

Not:

• på förra veckan ❌

This is very similar to English, which also says last week, not on last week.

Yes. Swedish often allows time expressions in different positions, though some versions sound more neutral than others.

Common version:

• Jag måste erkänna att jag glömde hennes födelsedag förra veckan.

You could also say:

• Jag måste erkänna att jag förra veckan glömde hennes födelsedag.

Both are understandable. The version with förra veckan at the end is very natural and straightforward.

Usually erkänna matches admit quite well here.

• Jag måste erkänna ... = I must admit ...

But erkänna can also mean confess, depending on context, especially if something more serious is involved.

In this sentence, it sounds natural and not overly dramatic. It suggests:

• the speaker is acknowledging something slightly embarrassing or regrettable.

Yes, but the meaning changes a little.

• Jag måste erkänna att... = I must admit that...

  • suggests reluctance, embarrassment, or honesty about something unfortunate

• Jag måste säga att... = I must say that...

  • more neutral, often just introducing an opinion or comment

So in this sentence, erkänna is better because forgetting someone’s birthday is something you admit, not just something you say.

Yes, that is natural.

In Swedish, glömma can take a direct object like:

• glömma ett namn = forget a name
• glömma nycklarna = forget the keys
• glömma hennes födelsedag = forget her birthday

Sometimes you may also hear glömma bort, but glömde hennes födelsedag is completely normal and idiomatic.

A simple breakdown is:

• Jag = subject
• måste = modal verb, present tense
• erkänna = infinitive verb
• att = conjunction introducing a subordinate clause
• jag = subject of the subordinate clause
• glömde = past tense verb
• hennes = possessive determiner
• födelsedag = noun
• förra veckan = time expression

So the overall structure is:

subject + modal + infinitive + att-clause

That pattern is very common in Swedish:

• Jag måste erkänna att...
• Hon verkar tro att...
• Vi hoppas att...