偶

偶々
tamatama
accidentally, unexpectedly

たまたまテレビを見ていた時, ちょっと感動した
Accidentally when I was watching it on the television, I was a bit impressed.

偶に
tama ni
occasionally, once in a while

嫌な世の中だけど、偶には良い事もあるよ
Iyana yo no naka dakedo, tamani wa yoi koto mo aru yo.
In this unpleasant society however, there is also good thing occasionally.