Short Answer: She's Rosa Cossete D'Elise, She's from Ace Combat Skies Unknown
Long Answer: She's the princess and daughter to the unseen King of Erusia (Basically AU Italy). Said King was a kind but also highly inexperienced man who shouldn't have been the king to begin with. Rosa made herself known as being incredibly charismatic despite her young age, her beauty and her speeches made her especially loved by the public, despite their rather poor King.
At the start of the story she wants to do right by her people, but is slightly Naïve, knowing the horrors of war but not experiencing it first hand.
Before the beginning of the War, Harling, Former President of Osea (AU America :P) creates a space elevator as a way to allow humanity to cross into space, though this also taps and controls lots of the Erusean Oil Supply.
This act makes a group of Young Erusean Officers extremely angry at Osea supposedly attempting to Exploit Erusia's Naivety of crossing into space, an idea that completely slipped by the King.
From this point we have the "Lighthouse" war, a war started by Erusea as a result of the space elevator. Erusea begins he war as a way to take control of the elevator to stop this exploitation.
This isn't before said officers introduce the idea of using UAVs (Unmanned Aerial Vehicles flown by AI) into the war to convince the princess the War will be completely clean, showcasing how it can destroy targets without killing civilians.
This works, and Rosa is tricked into believing this war will cause no casualties and thus her charisma leads her country into arms, and their willingness to fight against Osea. Afterwards the Eruseans use the space elevator as a constant power source to power their UAVs.
This backfires hugely near the end of the war. As the UAVs themselves fail to wage a quick and clean war (To the point where even the communication satellites get destroyed), Erusean Millitary officials absolutely HATE the princess for escalating the war, not knowing she was manipulated into it.
On their way to a safer location further away from the center point of the war. Her plane gets shot down by another Erusean plane, with a complete lack of communication during the chaotic war time, the pilot that shoots at her plane gets off completely scot free, despite the fact that attempting to do harm to a civilian/Royalty member/Ally is normally a massive war crime and treason, the war is borderline lawless due to the communication systems down, and the few Erusean pilots that witnessed it, do not reprimand said pilot for shooting her down.
Rosa gets a massive reality check of war, after her plane crashes on an Island that was used as an air/prison base, allies and such turn on eachother in what is almost every man for himself.
She's saved by a group of Osean criminals and refugees (Some of which locked up unjustly) who managed to escape from the chaos.
Knowing that she escalated the war to this horrendous degree, she vows to do everything she can to stop this war by any means, even going out of her way to throw a smoke canister while under fire from a squad of Erusean Radicals, allowing an Airstrike to save the lives of everyone that saved her.
From this point, she boards the space elevator as to shut down some of its main systems to stop Eruseans from using it to power their weaponry.
This works.....Until one of the UAVs, out of power, crashes into the space elevator, causing debris to fall, forcing the Refugees to evacuate.
Deciding to value the life of the refugees over her own to buy them more time to escape, she parachutes down from it, not before almost getting kabobbed by an accidental missle shot.
After the end of the war, she attempts to set up a relief plan to finally get Eruseans and Oseas relationship back where it should be, becoming fully aware of her countries needs beyond speeches, and finally bringing peace back to the nation.