成熟 せいじゅく分裂 ぶんれつじゃないです
seijukubunretsujanaidesu

Noun
Desu Copula
Negation Auxiliary

The polite negative form of 成熟分裂

1. It's not mature splitting.; It's not acting maturely and splitting [from someone/something].

Negative
Polite
Casual Register