Lucivar was reluctant at first.
He couldn't trust anyone, not after what he had experienced.
Even the notion of trusting someone was disgusting for him now, it was repulsive.
Of all the people in the world, he trusted no one but himself.
In this case, he decided to trust Ravenna—not because he trusted her as a person but because he trusted her thirst to become stronger. Knowing how she came to power, it became apparent that Ravenna was desperate to become stronger.
She doesn't want to lose control again because of her Predator Oculus ability.
She doesn't want to experience the same painful feeling ever again.
She wanted to be in control of her own actions.
Lucivar trusted her drive and he was instantly rewarded.
Knowing what Leandra was planning, Ravenna made haste to meet with Mirel earlier.