約束があるから断るわけにはいかない

N4 約束 yakusoku promise, appointment, arrangement N5 はい hai yes

N3 約 yaku / tsuzu.maru, tsuzu.meru, tsuzuma.yaka promise, approximately, shrink N3 束 soku / taba, taba.neru, tsuka, tsuka.neru bundle, sheaf, ream N3 断 dan / ta.tsu, kotowa.ru, sada.meru severance, decline, refuse

N5 〜から kara Indicates cause or reason, equivalent to because or since, connects two clauses explaining reason N5 〜が ga Marks the grammatical subject, highlights new information, can also show slight contrast in some sentences N5 〜に ni Indicates destination, target, arrival point, specific time, or person receiving an action N5 〜か ka Marks a question, alternative, or uncertainty, appears at the sentence end or between options N5 〜は wa Marks the topic of the sentence, indicates what the sentence is about, can contrast with another element, organizes main information