"Хотеть" is a verb directed at something. "Хотеться" is a reflexive verb and it goes by itself or directed at self. For example: "я хочу есть"/ "I DO want to eat", it's my active desire. "Мне хочется есть" / "I have a strong desire to eat". So, it's not my active doing, it's just what I'm thinking about right now.

хотеть = you want something consciously хотеться = something is wanted by itself, even if your mind is against it

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