The phrase "assertion if" is not correct and does not form a usable expression in written English.
It appears to be an incomplete thought and lacks clarity without additional context.
Example: "The assertion if true would change the outcome."
Alternatives: "claim that" or "statement that".
Their assertion, if true, would undercut a major element of the official version of the affair.
It's a curious assertion if one examines the shelves of "Big Six" fiction and poetry at any chain bookstore.
It is expressed succinctly in Evagrius's oft-quoted assertion: "If you are a theologian, you will pray truly; if you pray truly, you will be a theologian".
Still, shareholders might feel more confidence about that assertion if the bank had detailed just how much extra capital it might have to find.
One F.B.I. agent, John Peterson, testified that he could not say whether the assertion, if true, had any significance for Dr. Karim.
By late in the second half of a nonconference shocker, what had sounded like the overstatement of deluded youth resonated more as reasonable assertion, if not point of fact.
Such efforts support George Orwell's assertion that "if men would behave decently the world would be decent".
Secondly, one is only engaging in an attempt to silence if one is insincere in one's assertions — if one is attempting primarily to silence, rather than to assert the truth.
In previous elections, such assertions, if proven false, likely would have damaged the candidate who made them.
In a letter to Attorney General Eric H. Holder Jr., the seven said the assertions, "if true, suggest a possible violation of various federal criminal laws intended to safeguard our political process from the taint of bribes and political machine manipulation".
The assertions, if confirmed, would represent a rare military victory for the insurgency, which has been struggling since it lost the stronghold city of Qusayr near the Lebanon border on June 5.
