The phrase "fierce conviction" is correct and usable in written English.
It is often used to describe a strong and determined belief in something. For example, "The senator spoke with fierce conviction about the need to bring greater economic opportunities to the region."
Words stream from her with fierce conviction.
Scholars say she maintained a fierce conviction that almost no translator could do her husband justice.
But she has a magical way of expressing a fierce conviction.
In the best scene, the pregnant Sally returns from Paris and is confronted by her angry mother (played with fierce conviction by Diahann Carroll).
But he led with fierce conviction from the front lines, prepared to confront persistent rejection and slander, imprisonment, bombings and death itself.
If there was unanimity, it was in the fierce conviction that future leaders should come from their own ranks — "exclusively from this popular movement," Abu Omar said — not from exile groups, like the Syrian Muslim Brotherhood and secular movements.
She is interested in pretty much everything, and she sees no contradiction between having fierce convictions and keeping an open mind.
LONDON — I like the look of President Barack Obama's new Middle East envoy, a person with broad experience, the trust of Israelis, growing support among West Bank Palestinians and a fierce personal conviction that a peace accord is essential not only for the parties but for United States national security.
Many construe fierce political convictions as a sign of bias.
The young women I know -- Democrat, Republican and Independent alike -- have fierce political convictions.
None of this, however, bothers Barbara Montgomery, who has staged a rare revival of the play at La Mama Experimental Theater Club with the fierce and admirable conviction that even if prison camps have disappeared, inhumanity and injustice have not.
