Yes, I am fine. in Japaneselanguage _Hai, genki desu. in formal expression. _Un genki dayo in casual

Yes, I am fine. in Japaneselanguage _Hai, genki desu. in formal expression. _Un genki dayo in casual

=はい、げんき です。/ うん、げんき だよ。

http://www.nicovideo.jp/watch/sm42006761