The phrase "assertiveness against" is correct and usable in written English.
It can be used when discussing the act of confidently expressing one's opinions or rights in opposition to something or someone.
Example: "Her assertiveness against the unfair policies was commendable and inspired others to speak up."
Alternatives: "confidence in opposition to" or "firmness against".
Referendums give voters an artificial sense of empowerment and can formalise a previously vague sense of nationalist assertiveness against a perceived enemy.
The US has lifted a decades-old arms embargo on Vietnam in a historic move that follows the country's growing assertiveness against China's influence in the region.
One reason for Khartoum's assertiveness against the UN in Darfur is that it has learnt that the West, bogged down in Iraq and Afghanistan, seems to be full of empty threats on this issue.
The most important paradox is this one: the ultimate test of parliament's newly reinvigorated assertiveness against the executive is not whether it sets the terms for Brexit, but whether it will call a second referendum.
Mrs. Clinton, in the years since you announced your signature foreign policy initiative — the pivot to Asia Chinana has acted with increasing assertiveness against U.S. allies Japan and the Philippines, has maintained its alliance with North Korea despite Pyongyang's nuclear and missile tests, and has built and militarized islands out of whole cloth in the South China Sea.
In a vivid display of increasing assertiveness against the president, the Democratic side of the House rose to its feet in applause when Mr. Bush made what he intended to be a conciliatory reference to the defeat of his Social Security proposal last year.
Remember that assertiveness is a practiced skill.
There can also be an influence of a higher degree of assertiveness to go against physicians' recommendations to exhaust life-prolonging treatment options.
Beyond the territory of the former Soviet Union, Russian assertiveness regarding sanctions against Serbia, NATO expansion, and arms trade with developing countries has compelled several analysts to speak of a renewal of Russian expansionist tendencies and hence a return of Cold War tension between West and East.
On Wednesday, the prime minister fired the defense secretary in a rare public display of assertiveness by the civilian government against the army, as the fallout from a scandal centered on a memo written to Washington asking for its help in reining in the generals widened.
The Chinese have forged closer relations with his regime to ensure stability in a border country and to buffer against America's increasing assertiveness in Asia.
