The group trains so that everyone can pair with any other team member and use their powerful Unison attacks. But Shirabe is having trouble pairing up with anybody but Kirika, because of her inability to trust others.
The true meaning of becoming 
strong on your own
المعنى الحقيقي في أن تصبح قوياً بمفردك
Die wahre Bedeutung, selbst stark zu werden.
El verdadero significado de ser fuerte
El verdadero significado de ser fuerte
Le véritable sens
Вот истинное значение обретения силы.