Breakdown of Jeg tvivler på om historien er falsk.
jeg
I
være
to be
historien
the story
på
on / at / in (a language) / of (after nouns like end or start)
Questions & Answers about Jeg tvivler på om historien er falsk.
Why do we use om here instead of hvis, since both can mean 'if' in English?
We use om when dealing with an indirect yes/no question, meaning you could easily replace it with 'whether'. You use hvis for conditional statements, like 'if it rains'. Since the sentence expresses doubt about a yes/no scenario (is the story fake or not?), om is the correct choice.
Why is the word på included when the English translation doesn't say 'I doubt on'?
In Danish, the verb at tvivle (to doubt) strongly pairs with the preposition på when you are stating the specific thing you are doubting. It is a fixed phrase you will often see together: at tvivle på means 'to doubt [something]'.
Is it grammatically okay to put a preposition right next to a conjunction, like på om?
Yes, it is perfectly normal in Danish! Because the verb naturally requires på, you keep it even when the 'thing' you are doubting is an entire clause starting with om. Danish is quite flexible with letting prepositions introduce these types of dependent sentences.
Does om change the word order in the second half of the sentence?
om introduces a subordinate clause (a dependent part of the sentence), which has a strict word order rule: the subject always comes before the verb. Here, we see exactly that with the subject historien followed by the verb er. If you needed to add a small adverb like ikke (not), it would go between them: om historien ikke er falsk.