Love allows Manami to power up a target by confessing her feelings for them.
The more intense Manami's love is, the stronger the power transmitted to the target is. This empowering makes the target physically stronger and faster than usual.
Manami only has the ability to activate Love once every 24 hours, thus making it an ace in the hole that is best used strategically.
Love activates whenever Manami declares her love to whoever she loves most. In her case, it is Gentle Criminal.
Because of the usage limit offered by Love, both Manami and Danjuro consider it a trump card that must be strategically used as a last resort.