可能形 => Potential form N4
合う => do something together N3
~こと請け合い => I guarantee ... N1
Happens next
[合「あ」]う => To do A together/mutually N4
Secondary Verb
場合(は) => in the event of; in the case that ~ N4
~ににあわず (に似合わず ) => ~Different from N1
Evaluate
[可能系「かのうけい」] => Can, be able to, be possible to N4
Can, Should, Must