一心いっしん
isshinni

Adverb

1. wholeheartedly; single-mindedly; fervently; intently

Related to 一心
そのピアニストの演奏えんそうちゅう、彼かれらは一心いっしんみみかたむけた。
sono pianisutono ensōchū karerawa isshinni mimio katamuketa.
They were all ears while the pianist was playing.