Well, my main question here is whether Prussia is jealous over Austria for having Hungary because he (Prussia) has feelings for her, or was he just envious of Austria having a relationship while he doesn't have? (Although you may also comment on the other intriguing parts there like Hungary saying that her heart skipped because of Prussia.)
I would have think of it as merely an envy of Prussia over Austria for being not alone and not because he has feelings for Hungary but.... notice the lyrics of his character song, "My Song That Is Written By Me, For Me":
(English translation)
the 7th stanza of the song:
(The diary of the awesome me, bird month *piyo* day
I was really awesome today too!
Roar across the world, my song that is written by me, for me!
I won’t let Austria act so smug now
HUNGARY HAS TO APPRECIATE ME NOW
Italy, will you listen to it?
You’ll tell me what you think of my awesome song!
Hey West! Having beer is really tasty after singing!
He said, "HUNGARY HAS TO APPRECIATE ME NOW"
He wishes for Hungary to appreciate him. Does this confirm that he really does have feelings for her or what? What's your interpretation?