彼女の責任ではない。

she; her; her; girlfriend; sweetheart

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question

duty; responsibility (incl. supervision of staff); liability; onus

indicates location of action; at; in; indicates time of action; indicates means of action; cause of effect; by; and then; so; indicates continuing action; indicates certainty, emphasis, etc.

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

not; emphatic suffix