いったいどうして、彼はその提案を受け入れようとしているんだい。

...the heck (e.g. "what the heck?"); ...in the world (e.g. "why in the world?"); ...on earth (e.g. "who on earth?"); one object; one body; unity; one form; one style; one Buddhist image (or carving, etc.); generally; in general

why?; for what reason; how; in what way; for what purpose; what for

he; him; his; boyfriend

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

that (something or someone distant from the speaker, close to the listener; actions of the listener, or ideas expressed or understood by the listener); the; um...; er...; uh...

proposal; proposition; suggestion

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to accept; to receive; to agree

if; when; and; with; particle used for quoting (with speech, thoughts, etc.); quoting particle; promoted pawn; indicates question (sentence end)

to do; to cause to become; to make (into); to turn (into); to serve as; to act as; to work as; to wear (clothes, a facial expression, etc.); to judge as being; to view as being; to think of as; to treat as; to use as; to decide on; to choose; to be sensed (of a smell, noise, etc.); to be (in a state, condition, etc.); to be worth; to cost; to pass (of time); to elapse; verbalizing suffix (applies to nouns noted in this dictionary with the part of speech "vs"); creates a humble verb (after a noun prefixed with "o" or "go"); to be just about to; to be just starting to; to try to; to attempt to

yes; yeah; uh huh; negative verb ending used in informal speech (abbr. of negative verb ending "nu"); abbr. of particle "no"; abbr. of particle "ni" (used especially when it precedes the verb "naru")

title; subject; theme; topic; problem (on a test); question; counter for questions (on a test)