[決「けっ」]して~ない => Won’t, isn’t N3
Will, Decision, Doing
[事「こと」]だ => A is necessary/good (offering advice/suggestion) N3
Needs, Requirement
に[決「き」]まっている => A is a given, A must be the case N2
Information, Report
[事「こと」]ができる => Be able to A; can do A, Can A; be possible to A; N4
Causative, Passive, Volitional
に[限「かぎ」]った[事「こと」]ではない => It's not limited to A, it's not only A N1
Degree/ Level/Amount