「彼のことはよく知っていますよ」「ああそうですか」

he; him; his; boyfriend

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

thing; matter; incident; occurrence; event; something serious; trouble; crisis; circumstances; situation; state of affairs; work; business; affair; after an inflectable word, creates a noun phrase indicating something the speaker does not feel close to; nominalizing suffix; pretending to ...; playing make-believe ...; alias; aka; nickname; alternative name; also known as

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

nicely; properly; well; skillfully; skilfully; frequently; often

to be aware of; to know; to be conscious of; to cognize; to cognise; to notice; to feel; to understand; to comprehend; to grasp; to remember; to be acquainted with (a procedure); to experience; to go through; to learn; to be acquainted with (a person); to get to know; to concern

indicates certainty, emphasis, contempt, request, etc.; used when calling out to someone; used to catch one's breath or get someone's attention; yo!

Ah!; Oh!; Alas!; Yes; Indeed; That is correct; Hey!; Yo!; Uh huh; Yeah yeah; Right; Gotcha

so; really; seeming; appearing that; seeming that; looking like; having the appearance of

be; is

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