Takako-wa kanshin-da-nā. (Takako, I'm impressed.)

Situation 1: Mr. Okubo comes home and his daughter, Takako, serves him dinner.

たか子： 今日はお母さんが風邪で寝ているから、私が晩御飯を作ったのよ。

父： へえ、たか子は感心だなあ。うん、味もなかなかいい。

Takako: Kyō-wa okāsan-ga kaze-de nete-iru-kara, watashi-ga bangohan-o tsukutta-no-yo.

Chichi: Hē, Takako-wa kanshin-da-nā. Un, aji-mo nakanaka ii.

Takako: Today Mom's in bed with a cold, so I made dinner.

Father: Wow, Takako, I'm impressed. Yeah, and it tastes pretty good too.

Today let's look at the homonyms 感心 (かんしん, admiration) and 関心 (かんしん, concern), which have nothing to do with each other. 感心な is a na-adjective used to show that the behavior of someone, usually a child or young person, is admirable. It should not be used to describe a superior. In Situation 1, the dad says たか子は感心だ (literally, "Takako, you're admirable"). Using the noun-modifying form, he could say たか子は感心な子だ (Takako, you're an admirable girl). 感心する is its verb form and is used in the pattern ~に感心する, as in: 彼女(かのじょ)の犬(いぬ)がとても賢(かしこ)くて、買(か)い物(もの)までするのに感心した (Her dog's very clever; I was impressed that he even does the shopping).

Situation 2: Mrs. Okubo asks son Mitsuo about his interests.

母： 光男はゲーム以外に関心があることはないの？

光男： うーん...、プログラミングに少し。でも、ゲームをするのが一番楽しいな。

Haha: Mitsuo-wa, gēmu-igai-ni kanshin-no aru koto-wa nai-no?

Mitsuo: Ūn ..., puroguramingu-ni sukoshi. Demo, gēmu-o suru-no-ga ichiban tanoshii-na.

Mother: Mitsuo, isn't there anything other than games that interests you?

Mitsuo: Hmm ... programming, a bit. But I enjoy playing games most of all.

関心 (concern, interest) is a noun that does not appear in na-adjective or suru-verb form. It is used in the pattern Xに関心がある/ない (literally, "to have/not have interest in X"), as above. The antonym of 関心 is 無(む)関心, but 無関心 is a na-adjective used in this way: 最近(さいきん)は政治(せいじ)に無関心な学生(がくせい)が多い (Recently, lots of students are indifferent to politics).

Bonus Dialogue: Later, Mr. and Mrs. Okubo talk about Mitsuo.

妻： もう少(すこ)し子(こ)どもたちの教育(きょういく)に関心(かんしん)を持(も)ってよ。光男(みつお)の成績(せいせき)では、ぜったいにいい大学(だいがく)に 入(はい)れないんだから。

夫： 十分(じゅうぶん)関心を持っているつもりだよ。

妻 ： 子どもたちに、興味(きょうみ)や関心のあることをやればいいって言(い)ってきたのは、あなたよ。 そのせいで、光男は今もネットゲームしかやらない。

夫： ゲームが好(す)きなら、ゲームクリエーターになればいいよ。

妻： 漫画(まんが)が好きで漫画ばかり読(よ)んでいる子が、みんな漫画家(か)になれるわけじゃないでしょ？

夫： まあ、そうだ。ぼくも子供のころは漫画家になりたかったなあ。だけど、親に許(ゆる)してもらえるわけがないから、とにかく大学に入って会社(かいしゃ)に就職(しゅうしょく)して、お金(かね)をためてから 漫画家になればいいと考(かんが)えて、がまんして 勉強(べんきょう)していた。

妻： 感心(かんしん)な子供だったのね。

夫： うん。いつ会社をやめて漫画家になろうかと、今 (いま)でもよく考えている。

妻： 今でも？！　光男はあなたに似(に)たんだ、きっと。

Wife: Please show a little more concern about our kids' education. With his grades, there's no way Mitsuo can enter a good university.

Husband: I think I show enough concern.

Wife: It was you, dear, that told them to do what interests them. That's why Mitsuo still plays games nonstop.

Husband: If he likes games, he could become a game designer.

Wife: Not every child who likes comics and only reads that kind of thing can become a manga artist, right?

Husband: Well, I suppose not. I wanted to be a cartoonist when I was a child, but since I thought my parents wouldn't allow it, I decided I'd become a cartoonist after I'd entered college, got a company job and saved some money. So, I bit my lip and studied.

Wife: You were a good child.

Husband: Yes. But still now, I often think about when I should quit the company and become a cartoonist.

Wife: Even now?! Mitsuo takes after you, for sure!