'persevering effort' is correct and usable in written English.
It is often used to describe a sustained effort or dedication to a task, goal, or idea in the face of obstacles or challenges. For example, "By putting in a persevering effort, the team was able to successfully complete the project on time."
Many things of enduring value take slowness and painstaking effort: persevering through family crises, dialoguing across divides, earning a degree, growing into God.
Outsiders may well wonder whether it is worth persevering with their efforts to bring peace and prosperity to the benighted Balkans when, despite their best efforts, so many people there seem determined to kill each other.
"It can only be achieved through renewed, persevering and sincere efforts to resolve the Israeli-Palestinian conflict".
Despite these challenges, many are persevering in their efforts to develop novel cell therapies and improve patient outcomes for a variety of medical conditions.
"I persevered, and with effort and determination I'm standing here before you".
But the government persevered, making an effort to recreate some of the ornament, with disappointing results.
Don't we tend to vote for candidates who will persevere in their efforts to keep their campaign promises?
But public opinion supports him, and he must persevere in his efforts to enhance Israeli security through a fair and defensible peace.
Bethmann's message restating Germany's peace terms and inviting Wilson to persevere in his efforts was delivered on January 31 but was paradoxically accompanied by the announcement that unrestricted submarine warfare would begin the next day.
But it must also persevere in its efforts to build consensus within the United Nations to enact the ambitious reform agenda proposed by the secretary general and endorsed by all world leaders at last September's summit meeting.
