The phrase "also assert that a" is correct and usable in written English.
It can be used when you want to indicate that someone is making a claim or statement in addition to previous assertions.
Example: "The researchers also assert that a significant correlation exists between the two variables."
Alternatives: "also claim that a" or "also maintain that a".
Some also assert that a major reason Weight Watchers keeps its pay so paltry is that the overwhelming majority of its employees are women.
They also assert that a substantial chunk of the surplus should go toward dealing with an aging society's long-range problems, most notably the financial strains facing Social Security and Medicare.
They also assert that a formal complaint against Cruise and Liman was brought to the production's insurance company.
He'd probably concede his game was limited, but he'd also assert that a veteran looper might maximize it.
The same authors also assert that a small amount of sperm can be found in the urine of cats after electroejaculation even without the use of a chemical restraint or an ejaculation stimulus.
They also asserted that a prolonged and bitter strike in the mid-1990's had played a big role.
The three also asserted that a black male juror announced during deliberations that he did not like other blacks, saying, "Look at what they are capable of".
The article also asserted that a former Liechtenstein prime minister had assembled a network of banks, government workers and lawyers to help organized crime.
The report also asserted that a Swiss investment manager had made "thinly veiled" threats to a bank employee after learning that one of the bank's Madoff-linked investments could lose value.
Ms. Davis also asserts that a Filipino prostitute in Afghanistan was put on the Blackwater payroll under the "Morale Welfare Recreation" category, and that the company had billed the prostitute's plane tickets and monthly salary to the government.
The lawsuit also asserts that a Brown dean arranged for Mr. McCormick to face an administrative hearing rather than have his case heard by a panel of peers, faculty and deans.
