Learn Dutch: Wat vind je ervan? - What do you think of it?

Ervan means "of it". In Dutch, you cannot combine a preposition like van (of) with the pronoun het (it). Instead, you replace het with er (there) and attach it to the front of the preposition. So van het becomes ervan (literally "thereof").

Why do we use vind here instead of denk for "think"?

You use vinden when you are asking for someone's opinion, similar to "to find" in English (like "How did you find the movie?"). If you used denken (Wat denk je ervan?), it would sound more like you are asking for a logical thought or prediction, rather than a personal feeling.

Why is there no "-t" at the end of vind?

Whenever je or jij (meaning "you") comes directly after the verb, you drop the -t ending. Normally a statement is je vindt, but because this is a question, the word order swaps and it becomes vind je.

Could I use erover instead of ervan to say "about it"?