The ballroom proposal
Trump publicly suggested building a large ballroom onto the White House.
He claimed he would be willing to help fund or donate toward it himself (similar to past offers he made for renovations).

Would he have made money from it?
Evidence suggesting no financial benefit
The White House is government property, not privately owned.
Any construction would be:
Controlled by the federal government
Subject to contracting rules and oversight
There’s no record of Trump arranging contracts for his own companies to build it.
No formal project was approved or executed.