In the story I'm reading, a girl is given a gift from her boyfriend, after which she says, 「それをもらったの…私だけなのが幸せなのです…」I'm at a complete loss as to how to parse this.「私だけなの」is happy? "Only I am happy"? Somehow I find that interpretation unlikely, as the boyfriend isn't popular and the girl isn't the jealous type.
Could someone shed some light on this?
「それをもらったの…私だけなの」が、幸せなのです…
→「それをもらったのは私だけである(という)こと」が、幸せなのです。(literally) Happiness is that it was only me who received it.
What is happy is that I am the only person who received it (from the boy).
The second の before が is a nominalizer. The part in the brackets is a cleft-sentence, but は (or が) is replaced by an ellipsis (presumably because she is a taciturn character).
