この部屋はきれいではありません。

N5 この kono this N5 部屋 heya room N5 きれい kirei clean / beautiful N5 では dewa then, well, in that case

N3 部 bu / -be section, bureau, dept N4 屋 oku / ya roof, house, shop

N5 〜です desu Used at the end of a sentence, polite affirmative form, means to be depending on context N5 〜ます masu Used at the end of verbs, polite present or future form, makes the sentence more polite N5 〜で de Indicates where an action happens, means used, tool, cause, or material depending on context N5 〜の no Indicates possession, relation between nouns, nominal explanation, or turns a verb into a noun phrase N5 〜は wa Marks the topic of the sentence, indicates what the sentence is about, can contrast with another element, organizes main information