As a less-fortunate member of the Final Fantasy white mage brigade, FF3 White Mage is forced to fight in Not Ranked while her more fortunate brethern take on the DL's finest in Light. But no matter! As you have already anticipated, White Mage has healing. Lots of it, in fact. But what you might not know is that she has a weapon that has a good chance of causing Petrify. And it just happens to turn out that Rozalin is quite vulnerable to that status. So, White Mage can keep healing herself for practically forever, and just keep hammering away at her opponent until Petrify kicks in and wins the battle. Since Rozy just can't damage White Mage enough to keep her in a healing loop, this will be a cinch. Unusual battle strategies are the mark of NR, and White Mage hammering her way into a middle championship fits perfectly!
