Amused vs Bemused

The English words amused and bemused are confused by some native English speakers.

Amused

Amused means entertained or made to laugh.

I was amused by his antics
Do you think she was amused?
I am not amused

The noun amusement refers either to the state of being amused or to something that amuses

His obvious amusement pleased me
What amusements do you have planned for the party?

Bemused

Bemused means to find something confusing or puzzling.

I was bemused by his sudden decision to quit
You look bemused; should I repeat the question?
Bemused, he asked me to explain

The noun bemusement means confusion or puzzlement.

He stared at me in bemusement
I shook my head in bemusement

The Bottom Line

I'm sure the confusion between amused and bemused comes out of the fact bemused is less common and so when people hear it for the first time, they notice the similarity to amused and think the two words must have a similar meaning. In fact, amused and bemused mean two completely different things.

Just remember that you are amused at an amusement park (like Great America or Disneyland), and you are bemused when you don't understand.

The misuse of bemused is so common in writing that I often have to read the sentence several times in order to determine whether the person really meant bemused (confused) or amused(entertained). I remember one author who consistently said bemused to mean "slightly amused." I didn't find it amusing in the slightest. :-)
From: http://www.elearnenglishlanguage.com/difficulties/amusedbemused.html