'you are so clever' is 'dang-sin eun cham ddok-ddok-ha-gun-yo' in korean. =>dang-sin is 'you' in korean and 'ddko-ddok' is smart or clever,and 'cham' is 'so or really or very..'. 'you are so beautiful' is 'dang-sin eun cham a-rumdap-gun-yo' ==>'a-rumdapda' is 'beautiful' 'he is so hansome' is 'gu nun cham jal-sang-geot-yeo-yo' or 'gu nun mi-nam e da' ==>'gu' is 'he' and 'jal-sang-geot-da' is 'good-looking', and 'mi-nam' is 'hansome guy'

Well, it could be a bit weird to say 당신(Dahng-seen). So you need to know how to use it. 당신 is mostly said between married couples or strangers. 당신 refers to ‘You’ in English only when it's used as a word of the song. We call anyone ‘you’ in English, but it's not always possible to call anyone ‘너(Nuh) or 당신’ to Korean speakers. You'd rather call the lister's name instead of saying ‘당신’. It would be okay to call anyone ㅇㅇ(이름 name) 씨(ssi). You are so clever. ㅇㅇ씨 정말 똑똑하네요. → ㅇㅇSsi Jyuhng-mahl-tok-tok-hah-neh-yo. 너 정말 똑똑하네. → Nuh Jyuhng-mahl-tok-tok-hah-neh. (Between intimate friends of same age) You are so beautiful ㅇㅇ씨 정말 예뻐요. → ㅇㅇSsi Jyuhng-mahl-yeh-puh-yo. 너 정말 예뻐. → Nuh Jyuhng-mahl-yeh-puh. (Between... Blah blah blah) He is so handsome. 저 사람 정말 잘 생겼어요. → Juh-sah-ram Juhng-mahl-jahl-sehng-gyuht-ssuh-yo. 쟤 정말 잘 생겼어. → Jyeh Juhng-mahl-jahl-sehng-gyuht-ssuh. (......) Strictly speaking, ‘He’ is equal to ‘그’. But 그 is usually used by writers. We say 저 사람(If he looks older than us, 저 분 in honorific version) or 쟤(that boy or girl is/looks like the speaker's age). We say 걔(Gyeh) if we can't see ‘He’ right now. Hope this helps.