「愛<あい>」は元々中国語で、性（セックス）と関係の無いものにも使います。子供に対する愛や人類愛も有ります。相手を思いやる心です。「恋<こい>」は大和言葉<やまとことば>で、古い動詞「恋<こ>ふ」の名詞形です。性（セックス）に基づく感情で、自分中心です。相手の気持ちに関係なく、自分が相手の魅力にひかれている状態です。その恋が実って（相手が自分を受け入れて）恋愛に発展することも有りますが、一方的な恋（片思い）のまま終わることも多いです。子供に対する恋や人類に対する恋や動物に対する恋は有りません。 "愛ai" is originally in Chinese and also used for something which has no relation to the sex. There are also 愛 to a child and 人類愛philanthropy. It's the heart which sympathizes with a partner. "恋koi" is a traditional Japanese and a noun form of an old verb '恋<こ>ふ kopu→kofu→kou' . It's a feeling based on the sex and is a heart in oneself. It is in the state where someone is run over by the partner's charm regardless of a partner's feeling. It might be developed into 恋愛<れんあい loving each other> by 恋 achieving (the partner accepts you), but it finishes in many cases with one-sided love (unrequited love). There are no 恋 to a child, to the humankind or animals.

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