彼女は招待を受けようか受けまいか決めかねていた。

she; her; her; girlfriend; sweetheart

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

invitation

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 receive; to get; to catch (e.g. a ball); to be struck by (wind, waves, sunlight, etc.); to sustain (damage); to incur (a loss); to suffer (an injury); to feel (influence); to undergo (e.g. surgery); to take (a test); to accept (a challenge); to be given (e.g. life, talent); to follow; to succeed; to be descended from; to face (south, etc.); to be modified by; to obtain (a pawned item, etc.) by paying a fee; to be well-received; to become popular; to go down well

indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way

probably isn't (doesn't, won't, etc.); don't (doesn't) intend to; intend not to; must not; (when used in an imperative sentence) don't

to decide; to choose; to determine; to make up one's mind; to resolve; to set one's heart on; to settle; to arrange; to set; to appoint; to fix; to clinch (a victory); to decide (the outcome of a match); to persist in doing; to go through with; to always do; to have made a habit of; to take for granted; to assume; to dress up; to dress to kill; to dress to the nines; to carry out successfully (a move in sports, a pose in dance, etc.); to succeed in doing; to immobilize with a double-arm lock (in sumo, judo, etc.); to eat or drink something; to take illegal drugs