The sentence is wrong both grammar-wise and meaning-wise. We have three different things here, 'ja nai' , 'de WA arimasen' and 'desu'. "Ja nai" is casual speaking for 'am/is/are not', its polite and formal counterpart is 'de WA arimasen', again meaning the same; So one of them is enough and which to use indicates the level of formality in the sentence. 'Desu' is polite for 'am/is/are' and is not needed here. The sentence in correct form would be:
[ Watashi no nihongo (WA) sugoi ja nai ]
or
[ Watashi no nihongo WA sugoi de WA arimasen ]
Meaning: My Japanese is not impressive/great.
This can generally be translated as "Japanese is difficult" and "Japanese is hard for me."
This can be translated as "I like [the] Japanese [language]."
"I like..." is "私が...好きです" - "Watashi wa...ga suki desu" "I like Japanese" is "私が日本語好きです" - "Watashi wa Nihongo ga suki desu"
The answer to the first part"i like watching movies" is: watashi WA ega ga mimasu suki desu. #2 is Watashi WA ongako o nihongo ni kikimasu
suteki na neee kimi wa hontoni kawaii to moe desu. subarashii kira kira kyaaa desu I bow down to the kawaii
anata WA sugoi desu
watashi wa malay desu my name is malay
anata ga i nakute sabishii desu
Watashi WA ii desu yo
watashi wa namae wa inu desu
if you are asked "ogenki desu ka?" (are you well/ok) you can reply with genki desu - I'm fine maamaa - so so okagasama de - thanks to you genki dewa arimasen - not ok genki ja nai desu - not ok casual
__(item that is great goes here)__ WA sugoi desu.