Málsgreinin er ekki auðveld, en ég skil hana betur núna.

Málsgreinin means the sentence here.

A few useful details:

• The basic noun is málsgrein.
• It is a feminine noun.
• The ending -in is the definite article attached to the noun, so:
  • málsgrein = a sentence
  • málsgreinin = the sentence

Depending on context, málsgrein can also mean paragraph, but in this sentence the meaning is most naturally sentence.

Yes. In Icelandic, the is usually added to the end of the noun instead of being written as a separate word.

So:

• málsgrein = sentence
• málsgreinin = the sentence

This ending changes depending on gender, number, and case. Here, málsgreinin is:

• feminine
• singular
• nominative
• definite

It is nominative because it is the subject of er.

Because the adjective must agree with málsgreinin, and málsgrein is a feminine singular noun.

So the adjective auðveldur (easy) changes form:

• auðveldur = masculine
• auðveld = feminine
• auðvelt = neuter

Since málsgreinin is feminine, you say:

• Málsgreinin er ekki auðveld.
• The sentence is not easy.

If the noun were neuter, then auðvelt would be correct.

Because in Icelandic, ekki usually comes after the finite verb.

So:

• er ekki = is not
• skil ekki = do not understand

That is why you get:

• Málsgreinin er ekki auðveld
  • literally: The sentence is not easy

This is a very common word order pattern in Icelandic.

Yes. En here means but.

It connects two clauses:

• Málsgreinin er ekki auðveld
• en ég skil hana betur núna

So the full idea is:

• The sentence is not easy, but I understand it better now.

In many cases, en works very much like English but.

Skil is the 1st person singular present form of the verb skilja, which means to understand.

So:

• skilja = to understand
• ég skil = I understand

A few present-tense forms are:

• ég skil = I understand
• þú skilur = you understand
• hann/hún/það skilur = he/she/it understands

So ég skil hana betur núna means I understand it better now.

Hana means her/it and refers back to málsgreinin.

Since málsgrein is a feminine noun, the pronoun used for it is the feminine pronoun:

• hún = she / it
• hana = her / it

Here the pronoun is the object of skil, so it appears in the accusative form:

• nominative: hún
• accusative: hana

So:

• ég skil hana = I understand it

Even though English uses it, Icelandic uses the pronoun that matches the noun’s grammatical gender.

Because hana is the accusative form, and the verb skilja takes a direct object in the accusative.

Compare:

• Hún er ekki auðveld. = It/She is not easy.
  • Here the pronoun is the subject, so nominative hún is used.
• Ég skil hana. = I understand it/her.
  • Here the pronoun is the object, so accusative hana is used.

This is a very important Icelandic pattern: pronouns change form depending on their role in the sentence.

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

Here it modifies the verb skil (understand), not a noun. So Icelandic uses the adverb:

• vel = well
• betur = better
• best = best

So:

• ég skil hana betur núna = I understand it better now

By contrast, betri would describe a noun:

• betri málsgrein = a better sentence

So the distinction is:

• betri = better (adjective)
• betur = better (adverb)

Núna means now.

It tells you when the speaker understands it better:

• ég skil hana betur núna = I understand it better now

Its position is natural and common. Icelandic often places time words like núna in a similar way to English, especially at the end of a clause.

You could also hear different word orders in other contexts, but this sentence is completely normal.

Málsgreinin is in the nominative singular definite.

Why nominative?

Because it is the subject of the clause:

• Málsgreinin er ekki auðveld
• The sentence is not easy

The subject of er (is) is in the nominative.

That contrasts with hana, which is in the accusative because it is the object of skil.

Yes. En ég skil hana betur núna has normal word order.

The pattern is:

• conjunction: en
• subject: ég
• verb: skil
• object: hana
• adverb: betur
• time word: núna

So it is a straightforward main clause.

A useful thing to know is that Icelandic often follows verb-second word order in main clauses. Here, since the subject comes first inside the clause, the finite verb naturally comes right after it:

• ég skil ...

If some other element were moved to the front, you would often see inversion:

• Núna skil ég hana betur.
• Now I understand it better.

Both are possible, but the version in your sentence is the most neutral.