"ultimately know" is a correct and usable phrase in written English.
It is often used to convey the idea that after some period of consideration or observation, one has come to some conclusion or understanding. For example, "After weeks of research, I ultimately knew which car to buy."
"We don't ultimately know why he was gathering this data".
The scriptural passage spoke of life's mortality and promised that the pious will ultimately know the blessings of Allah.
Of course, the fundamental difference between entrepreneurs and con artists is that con artists ultimately know that the fantasies they're selling are lies.
"We may not ultimately know the farm where these came from," Dr. David Acheson, the agency's associate commissioner for foods, told reporters in a conference call.
"I don't want to give the impression that this is obviously a good thing in the sense that we don't ultimately know the consequences of this earlier flowering," he said.
Shen also quotes Schweizer on the Clintons: "We cannot ultimately know what goes on in their minds and ultimately provide the links between the money they took and the benefits that subsequently accrued to themselves, their friends, and their associates".
Fischer was a man who was ultimately known by no one, not even himself.
Ms. Pierce became the youngest member of the Transcendentalist Painting Group, and was ultimately known for her subtly reflective poured resin works.
Those hours of work and having that proper direction, I ultimately knew or did not ever lack belief that I would ultimately win".
It assumes that the market ultimately knows best, and that share price and volume patterns are the most prescient indicators of a stock's direction.
But they ultimately knew it was a good idea, and I ended up being obsessed with camp and going back for six more summers.
