"I do not like this jewelry."
Translation:Ich mag diesen Schmuck nicht.
Read up on nicht here: http://german.about.com/od/grammar/a/The-Position-Of-Nicht.htm
Depends on case and singular/plural/gender. See the chart here:
Basically, you put the same ending on diese that you would put if you were using the definite article instead. So, if you would say, "Ich mag diesen Schmuck." you could think normally you would say, "Ich mag den Schmuck." and see the -en ending (masculine accusative) is what you need, so you have to use "diesen". I realize that's still complicated, but it's the best way I can explain it.
Why diesen? Because Schmuck is plural? And which gender Schmuck is? It's quite frustrating to lose last heart with such a confusing question.
I see, because this is accusative case, but how should I know that this word is masculine. I've tried the internet, didn't find gender of Schmuck.
I've found a really simple way if I want to check the gender of a noun is to have Google Translate open in another tab and just type in the [Noun] in English. Then you can tell the gender by whether it's der, die or das. Schmuck is masculine by the way. Hence why it becomes diesen.