Both "als" and "indien" can mean "if", in that context they are synonymous. However, "als" can also mean "when", whereas "indien" cannot.
I am not a native Dutch speaker. But according to Duolingo, the conjunction "mits" is translated in English as "..., but only if...", so I guess it does really have an absolute conditional meaning.
Simius is correct. Apart from the meaning, 'als' is a bit more colloquial, 'indien' is a bit more formal.
Does this mean that there exists no grammatical difference between "als" and "indien"?
One of the first things I learnt during my in the Netherlands; everyone carries their own weight.
If someone invites you to an event, restaurant, bar, or wherever, the person who invited you doesn't pay for you. You pay for yourself.
When the English sentence uses as if - He acts as if nothing is wrong - Hij doet (als)of er niets aan de hand is
When the English sentence uses if/whether
- I wonder if/whether he comes - Ik vraag me af of hij komt
- I don't know if he did it - Ik weet niet of hij het gedaan heeft
- If/whether you like it or not - Of je het leuk vindt of niet
Why is it not "...indien betaalt zij."? I thought that the word order in the second clause stayed the same only when using dus, en, maar, of, want. Why has it not changed here? Isn't this a Subordinating Conjuntion?
For co-ordinating conjunctions -- the common ones you mentioned -- govern the V2-Word Order when used to initiate a clause.
For subordinate conjunctions -- indien included -- all verbs are pushed to the end.
You're probably aware of this already ^.^
As a subordinate conjunction, indien requires all verbs within the clause it initiates to be placed at the end, thus:
[...] indien zij betaalt.
[...] als zij betaalt.
[...] dus betaalt zij.
[...] maar betaalt zij.