1.I decided that I wouldn't talk to her !
Correct. Better: "I decided not to talk to her"
2.I decided that I wouldn't talk to her again!
Correct, but it means you talked to her before, and will not to it again.
Better: "I decided not to talk to her again"
3.I decided not to talk to her again!
4.I decided that I never talk to her!
Incorrect. You must use a modal verb (فعل وجهی) after "decide that".
5.I decided that I would never ever talk to her again.
Correct. Better: "I decided to never ever talk to her again".
"Never ever" is informal.
#4 is wrong. #1, 2, 5 are unnatural. When the "decide" and the main verb have the SAME subject, use "decide to do".
If the two verbs have DIFFERENT subjects, use "decide [that]".
You can remove "that".
I decided to go (not "I decided that I will go")
My friend decided to cook dinner tonight
We decided to watch a movie
I decided [that] you don't have to go
My friend decided [that] I should cook dinner
We decided [that] this movie is boring