Breakdown of Wir haben den Roman, den du meinst, schon gekauft.
du
you (informal singular)
kaufen
to buy
haben
to have
wir
we
Questions & Answers about Wir haben den Roman, den du meinst, schon gekauft.
Why are there two dens right next to each other (... den Roman, den ...)?
The first den is the definite article for Roman ("the novel"). It is in the accusative case because it's the direct object of the main sentence (the thing being bought). The second den is the relative pronoun ("that" or "which"). It is also masculine and accusative because it refers back to Roman and is the direct object of what you are thinking of (meinst).
Why does the relative clause , den du meinst, interrupt the main sentence?
In German, a relative clause usually jumps in immediately after the noun it describes. Here, it describes den Roman. Because of this, it temporarily pauses the main clause (Wir haben den Roman ... schon gekauft) and must be bracketed by commas.
Why is the verb meinst placed right before the second comma?
A relative clause is a type of subordinate (dependent) clause. In German, the conjugated verb in these clauses is always pushed to the very end of that specific clause. The relative clause finishes at the second comma, so meinst is placed exactly there.
How do I know when to use meinen for "to mean" instead of bedeuten?