그리워하다: miss, long for, pine for

I miss you badly.

He still pines for his dead wife.

사랑에 빠지다: fall in love with, head over heels

나는 그녀에게 첫눈에 반했다: I fell in love with her at first sight.

그는 그녀에게 푹 빠졌다. He is completely head over heels about her

사랑에 빠져있다의 다양한 표현들: adore, love, be infatuated with, be in love with, fall for, long for, fall madly in love with, be taken with, desire

그는 그녀를 완전히 사랑한다: He absolutely adores her.

그는 그녀에게 완전히 미쳐있다: He is completely infatuated with her

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informal: be mad about, be crazy about