私にはわからない。

I; me; private affairs; personal matter; secrecy; selfishness

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

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

to understand; to comprehend; to grasp; to see; to get; to follow; to become clear; to be known; to be discovered; to be realized; to be realised; to be found out