Jag vet inte vad som står i mejlet.

Swedish often separates two meanings that English puts under know:

• veta = to know a fact, piece of information, or answer
• kunna = to know how to, or to be able to

Here the speaker does not know the information in the email, so veta is the right verb.

• Jag vet inte = I don’t know
• Jag kan inte = I can’t / I’m not able to

Because this is a main clause, and Swedish main clauses normally put the finite verb early in the sentence. The negative word inte usually comes after that finite verb.

So:

• Jag vet inte = correct
• not Jag inte vet in a main clause

A useful comparison:

• Main clause: Jag vet inte
• Subordinate clause: ... eftersom jag inte vet = ... because I don’t know

Literally, står means stands. But in Swedish, stå is very often used about written text.

So det står i mejlet means something like:

• it says in the email
• it is written in the email

This is completely natural Swedish. The same verb is used for signs, messages, letters, websites, and so on.

Here som is needed because vad functions as the subject of the embedded clause.

A simple way to think about it:

• vad = the thing that is written
• som står i mejlet = that is written in the email

In embedded questions, Swedish often uses som when the question word is the subject:

• Jag vet vem som kommer = I know who is coming
• Jag undrar vad som hände = I wonder what happened

But if the question word is not the subject, som is usually not used:

• Jag vet vad han skrev = I know what he wrote

Because vad står i mejlet? is a direct question:

• Vad står i mejlet? = What does the email say?

But after Jag vet inte, you need an embedded question, not a direct question. Embedded questions do not use the same word order as direct questions.

So the correct form is:

• Jag vet inte vad som står i mejlet.

I mejlet means in the email, referring to the content inside it.

• Vad står i mejlet? = What does the email say?

By contrast, på mejl usually means by email or via email, referring to the method of communication.

For example:

• Jag fick det på mejl. = I got it by email.
• Det står i mejlet. = It says so in the email.

So here i is the natural choice because the sentence is about the text inside the email.

Because mejl is a neuter noun:

• ett mejl = an email

The definite singular form of a neuter noun usually ends in -et:

• ett mejl = an email
• mejlet = the email

So i mejlet means in the email.

Yes. Mejl is a standard and very common Swedish spelling.

You may also see:

• mail in some informal writing
• e-post or e-postmeddelande in more formal contexts

But mejl and mejlet are very normal everyday Swedish.

Not in standard Swedish in this structure.

You can say:

• Det står i mejlet att ... = It says in the email that ...

But when you have vad in this sentence pattern, standard Swedish uses:

• vad som står i mejlet

So for learners, the safe and correct form is:

• Jag vet inte vad som står i mejlet.