不~ (negative prefix)

She sighed at her unhappy fate.

She was terribly cold toward me.

She's quite pretty but looks unhealthy.

In short, he was the careless one.

Yoko thought it was impossible to keep living alone.

She categorically declared that he was dishonest.

She was ashamed of her carelessness.

She felt anxious about her future.

She accused me of being insincere.

She gave me an awkward smile.

She put the result down to her own carelessness.