彼女は暗闇を恐れる。 She's afraid of the dark. 私は熊が怖い。 I am afraid of bears. the last one literally means: "as for me, bears are scary"

Markoさん、こんにちは。 As René answered, 怖い(こわい) means ‘scary’ or ‘be afraid of sth’, and it’s an adjective. Predicative usage; e.g. 夜道(よみち)は怖いです。(I am afraid of walking outside after dark.)(夜道 literally means ‘the street in the night’) 彼女は犬が怖い。(The dog is scary for her.) or 彼女は犬を怖がっています*。(She looks she is afraid of dogs.) ＊こわがるis used for describing the action of the third person, which can be translated as ‘look’ or ‘seem’. Attributive usage; e.g. 怖い話をしないでください。(Don’t tell me the scary story.) Then, 恐れる(おそれる) is a verb and means like ‘fear’ or ‘be frightened of sth’, and more formal than 怖い. e.g. 彼は真実(しんじつ)を語(かた)ることを恐れている。(He fears telling the truth.) 　 　 私は死を恐れない。(I’m not frightened of death.) Overall, ‘to be afraid of sth’ in Japanese is こわいas an adjective, and おそれる or こわがる (for the third person) as a verb. Hoping this helps :D