"I trust a friend too much" is incorrect? It wanted believe instead of trust and friends instead of a friend, but I'd expect chingudul for friends unless I'm misunderstanding something about this noun.
You don't necessarily have to put "-들" behind a word to make it plural. Using trust instead of believe wouldn't have made it incorrect.
Would it be wrong if I use 너무 많이 in this sentence to mean "too much"? Is there a difference and when do I use which?
I vaguely recall a sentence in a previous lesson where 너무 많이 was used in "Don't study too much" or something like that.
This was a terrible exercise. It's not you. it's duolingo. The word bank didn't provide word options matching the translation.
Is there a reason 너무 is translated to "too much" here, instead of "very"?
It can and usually IS used this way. The translation of the sentence is a bit wrong in this example in my opinion
We make fun of people. I believe in friends too much. Things are pretty bleak.