私は彼をよい先生だと考えていた。

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

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

he; him; his; boyfriend

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.

good; excellent; fine; nice; pleasant; agreeable; sufficient (can be used to turn down an offer); ready; prepared; profitable (e.g. deal, business offer, etc.); beneficial; OK

teacher; master; doctor; with names of teachers, etc. as an honorific; previous existence

be; is; indicates past or completed action; indicates light imperative

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

to think about; to take into consideration; to ponder; to reflect; to try to come at a conclusion; to think over (something); to intend; to decide (to do); to plan; to come up with; to devise; to scheme; to predict; to anticipate; to expect; to suspect; to doubt; to consider (somebody to be something); to look on