The phrase "disillusioned that" is correct and usable in written English.
It can be used when expressing disappointment or loss of faith in something or someone.
Example: "She was disillusioned that her favorite author had turned to writing commercial fiction."
Alternatives: "disappointed that" or "disenchanted with".
Disillusioned that yet again, right as the eyes of the world were taking seriously the very real facet of rape and sexual assault on our college campuses, that with one story's unraveling so too goes all that progress?
He left disillusioned that their advice was not heeded.
But he eventually walked away from his career, disillusioned that he was not receiving the royalties he thought he deserved, and he became an insurance salesman in suburban Philadelphia.
"Many of these customers feel abandoned by their banks and disillusioned that they have lost personal contact," said Alan Levan, the chairman of BankAtlantic, which has $5.8 billion in assets.
But after his death, newspapers in Scotland reported that Mr. Miralles had told a friend, even as he was dying, that he was disillusioned that the project had become so politicized.
The lawmakers had been feeling disillusioned that they were carrying Mr. Obama's water on the bill, while Obama aides triangulated and promised that the bill would "improve" in the Senate.
By clearing the 5 percent hurdle for representation in the state Parliament, the Left Party, which is also made up of former Social Democrats disillusioned by that party's centrist policies of recent years, scored a significant victory.
After the February Revolution of 1917, which overthrew the Romanov dynasty, he became chief of staff to the provisional government's commander in chief, Mikhail V. Alekseyev, but was quickly disillusioned by that government's inability to maintain discipline in the army.
By then, it meant white boys with holes in their jeans playing guitars, which was great for us at the time, but I became disillusioned with that meaning pretty quickly.
In the end, however, he was left bitterly disillusioned, acknowledging that Blair and Gordon Brown were redistributing to the poor, but profoundly offended by the mean-spirited way in which he thought they went about it.
