Failkura has no will and can’t keep her emotions in line, a key factor for any solider. The 2nd Databook states that there are times she wants to give up on life, in other words, to kill herself! Suicide! Over what? Nothing but her childhood crush leaving her. Something as minor as that makes her want to die. She’s crying left an right, over Sasuke leaving, over her own uselessness, over being a burden, over Sasuke not caring for her. FFS, she barely knew Sasuke, yet started wailing at the thought of him being dead. Over someone she didn’t even know!
Hinata on the other hand, knows how to pull herself together. Her own brother who she loves dearly and has spent years with, dies in front of her very eyes, gasping for breath as the life leaves his body, and she is so shaken by his death she starts shaking and tears flow down her face like nothing we’ve ever seen from her. Even with such a massive burden turmoiling her mind, she was able to set her emotions aside in order to help bring the heart of the alliance, Naruto, back on his feet in order for them to continue fighting the enemy.
Even in The Last, when she thought Toneri had killed Naruto, the person she cares for more than anyone else, the furthest her expression went was a look of distress. And people want to say Hinata would fall apart if Naruto died lol.
The Will of Fire states that the entire village is like a large family unit and every Konoha shinobi with the Will of Fire loves, believes, cherishes, and fights to protect the village, as previous generations had done before them. Remind me who was it that wanted to leave the village for a rogue ninja VS who it was that abandoned their love interest to save their village and the world?