Rosine vs Laser Lance: who would win?

Laser Lance favored — Slight edge (~55%)

Rosine · Berserk · Base

Tier
8-A
Attack Potency
Multi-City Block Level
Speed
Subsonic+, up to Supersonic
Durability
Multi-City Block Level

Laser Lance · Ben 10 · Base

Tier
8-A
Attack Potency
Multi-City Block Level
Speed
Relativistic
Durability
Unknown

A heuristic estimate from normalized VS Battles Wiki stats: tier, attack potency, speed and durability.