This is a strategy used by no-hit runners (check out Faaraz Khan or Squilla), but it’s really a good strategy for anybody struggling with Rom. She won’t attack when you first encounter her. Kill the spiders, and beat her face with R1/L1's to build your beast meter. She’ll take next to no damage so you won’t trigger her second phase.
Once the beast meter is filled, equip your weapon and use fire paper. R1/L1/L1/R1 should knock her out of her transition. After that just R1 spam until it’s over. No hits and no cycles.
