~(ㄴ/은/는) 것, ~(ㄴ/은/는) + Noun/Pronoun. There are some variations on the ~ㄴ 것, or the general ~ㄴ + Noun form, a little involved but very useful to know. First, it depends on the word's role: verb or adjective. Note that Korean adjectives are almost like verbs unlike the English counterpart. They are close to verbs in form, but differ in places as they only represent a "state" as opposed to verbs' "action". - adjective (예쁘다 example): 나는 예쁘다: I am pretty / 예쁜 여자아이: A pretty girl. - verb (가다 example): 나는 학교에 간다: I go to school / 학교에 가는 햑생: A student (who is) going to school. Both 예쁜 and 가는 above modify a noun. ~는 것 is just one case of this general form where the noun happens to be 것(thing). The important thing is to note 예쁜, not 예쁘는, for 예쁘다, and 가는 for 가다: ~ㄴ vs ~는. ~는 form is possible only for verbs since it denotes an "ongoing action" which adjective by definition can't have. Verbs on the other hand can have the ~ㄴ form, as in 학교에 간 학생. In this case, it represents the past (or present perfect for a result) tense, meaning it is a student who has "gone" to school. So, ~는 것 is for verbs only, and ~ㄴ 것 has a slightly different meaning between verbs and adjectives. This is the first step in understanding this important form. Your sentence 그 사람 너무 예뻐는 거 있어요 is structurally wrong. 그 사람 너무 예쁜 거 있어요 is structurally ok but still doesn't make sense. You can compare these: - 그 사람 너무 예뻐요: He is so pretty. - 그 사람 너무 예쁜 것 같아요: I think he is so pretty. (것 = that ...) - 그 사람 너무 예쁜 것(을) 가지고 있어요: He has something that is so pretty. (것 = thing).

When I take a step to you with a bunch of sweet-smelling flowers, what would you look at first? The modifier, or the person? 'The person that is very pretty' (In this phrase, the comma should be omitted): In English, you turn your eyes on the person first while treating the following clause, the flowers, as a postmodifier; 'the person that is very pretty' In Korean, you turn your eyes on the flowers, the premodifier, first and then you have a look at the person; '매우 예쁜 사람'.

(으)ㄹ is for the future tense (a meal I will cook, for example). 는 is for the present tense (a meal that I cook). (으)ㄴ is for the past tense (a meal that I cooked). This applies to verbs.

는것 is for turning verbs into nouns. ㄴ/은/는/을/ㄹ is for turning adjectives and verbs into their noun modifying forms. These forms go before, not after, the noun. Also, what you wrote in English is just a phrase, not a sentence. There shouldn't be 있어요 in the sentence just to say "the person that is very pretty". If you were saying "There is the person that is very pretty", then you would use 있어요. But that is not a complete sentence and has no verb, so no verb in Korean is needed either. Just "그 너무 예쁜 사람"