although; despite; even though; and yet
whereas; while
if only; I wish
in order to
約束したのに来なかった。
You promised, and yet you didn't come.
せっかく作ったのに食べない。
I went to the trouble of making it, but you won't eat it.
知っているのに教えてくれないんです。
Even though you know, you won't tell me.