Hún segir að maginn hennar sé betri eftir heita súpu.

Að introduces a subordinate clause and means that.

So:

• Hún segir = she says
• að maginn hennar sé betri... = that her stomach is better...

In English, that is often optional: She says her stomach is better. In Icelandic, að is very commonly kept.

Sé is the present subjunctive of vera = to be.

Here, sé is used because the clause is being reported through hún segir að... = she says that.... Icelandic often uses the subjunctive in reported speech or when the speaker is presenting something as someone else’s statement rather than as a plain fact.

So:

• er = is, indicative
• sé = be, subjunctive

In real Icelandic, you may sometimes also hear er in similar sentences, but sé is very common in this kind of indirect/reporting structure.

Yes, it can be hard at first, because it does not look much like vera.

The verb is:

• infinitive: vera = to be
• present indicative: er = is
• present subjunctive: sé = be

So in this sentence, sé is just a form of vera.

Because maginn means the stomach, while magi means just stomach.

Icelandic usually adds the definite article to the end of the noun:

• magi = stomach
• maginn = the stomach

In maginn hennar, Icelandic literally has something like the stomach of hers, which is the normal way to say her stomach.

Because hennar is the genitive form of the pronoun hún and is used for possession.

Compare:

• hún = she
• hana = her, as a direct object
• henni = her, as an indirect object / dative
• hennar = her / hers, for possession

So:

• maginn hennar = her stomach

This is one of the big differences from English: Icelandic changes the pronoun form depending on grammatical role.

That is the normal pattern with this kind of possessive in Icelandic.

So Icelandic says:

• maginn hennar = her stomach

rather than putting the possessive first the way English does.

A useful way to think of it is:

• English: her stomach
• Icelandic: the stomach hers

That is not a literal translation you should use, but it helps explain the structure.

Because betri is an adjective, while betur is an adverb.

Here, better describes the stomach, so Icelandic uses an adjective:

• maginn ... sé betri = the stomach is better

But if you were describing how someone does something, you would use the adverb:

• henni líður betur = she feels better
• hann syngur betur = he sings better

So:

• betri = better, adjective
• betur = better, adverb

Betri is the comparative form of góður = good.

That means:

• góður = good
• betri = better
• bestur = best

In this sentence, betri agrees with maginn, which is singular and masculine. Predicate adjectives in Icelandic usually agree with the subject.

It is nominative singular.

That is because maginn is the subject of the clause:

• maginn hennar sé betri = her stomach is better

The thing that is better is the stomach, so it appears in the nominative.

Heita súpu is accusative singular.

• súpa = soup
• heita súpu = hot soup, accusative singular

This happens because eftir can govern different cases depending on meaning. In this sentence it means after in a temporal sense, and here it takes the accusative.

So:

• eftir heita súpu = after hot soup

Because the adjective has to agree with súpu.

Here:

• súpu is feminine singular accusative
• so heitur = hot becomes heita

So the phrase is:

• heitur = hot, dictionary form
• heita súpu = hot soup, with the adjective matching the noun in gender, number, and case

This kind of agreement is very important in Icelandic.

In natural English, you would usually understand it as after having hot soup.

The Icelandic phrase does not spell out the action. It simply says after hot soup, and the listener understands the intended meaning from context.

So it can be interpreted as something like:

• after eating hot soup
• after having hot soup

depending on the situation.

Most of it is straightforward, but two parts may feel especially non-English:

1. maginn hennar
   Icelandic uses a definite noun plus the possessive after it.

2. sé
   The subjunctive in reported speech is much more visible than in modern English.

So even if the meaning is simple, the grammar shows some very typical Icelandic patterns:

• noun + suffixed article
• possessive after the noun
• case marking
• adjective agreement
• subjunctive in a subordinate clause