being scared, because ... is scary
彼は恐くて青くなった。
He turned pale with fear.
君は殺される夢が恐くて両親を殺したと言った
You said you killed your parents because you were afraid of dreaming that you would be killed.
— The Garden of Sinners: Paradox Spiral (2008)
彼女には恐くて話しかけたことがない。
I've never spoken to her because I'm afraid of her.