はずがない => Cannot be A, should not be A N4
Sentence Endings
ずにはおかない/ないではおかない => Will definitely A, N1
Will, Decision, Doing
ずにはすまない/ないではすまない => A must be done N1
Potential, Possibility
ずにはいられない/ないではいられない => Can't help but A; A is unavoidable N2
Will, Decision, “Doing”
はずがない => Cannot be A, should not be A (when describing a situation, not the actions of the subject) N3
Sentence Endings
てしょうがない/てしかたがない => Very A; Really A; Extremely A N2
Degree, Level, Amount
ことはない => Not necessary N3
Needs, Requirement
に[違「ちが」]いない => Without a doubt, A N2
Information, Report
が[早「はや」]いか => As soon as A occurred, right after A N1
Time, Situation
に[難「むずか」]くない => It's not hard to A N1
Adjectival, Descriptions
なくてはいけない => Must do A; have to A N4
Can, Should, Must
ことは~が => Although A is true, C N3
Contrast