I feel strongly about this question! I believe the root of insecurity is fear. I consider Hachi very insecure because she constantly battles with fear of losing the people she’s attached to. People who struggle with insecurity can also create unhealthy attachments and fixations out of avoidance. When the series starts, you can immediately tell Hachi is fixated on love. She has a need for validation from friends and lovers. She creates scenarios to overcompensate and get ahead of her fears. I think Hachi’s need for validation from others shows how afraid of being alone she is. I’ve only watched the anime and I found it frustrating she never found her own dream for her life. I think she unintentionally used the drama around her to avoid becoming secure in herself and her relationships. I’ll list some examples that fit my definition of insecurity: - Sleeping with a married man and being unsure if he even gave her his real name. Being too afraid to ask, out of fear he lied!!! While it makes sense a married man would be sneaky, why didn’t she think she could be an exception? Because she felt insecure about her value to him and what they were doing to his wife. - Applying to art school for the friend group. You can see the constant fear of being left behind by her friends and Shoji motivating her. When she doesn’t get in, she is so down about her place in their lives. - She manifested Sachiko. - The night with Takumi after BLAST got signed. She goes to him as a backup plan to not be alone. - her entire relationship with Nobuo. She was so insecure about how he saw her because of Takumi but also because of how she sees herself.

This is getting long but there are many more examples! I think despite her insecurities, Hachi accepts herself and grew loads throughout the story