@martha confeared ain't wrong but let me break it down for you in more detail.
There are two mirrors (let's say A and B). The mirror A will be given to the victim by the offender who keeps the mirror B with themself. If the victim was to look at mirror A while the offender is facing the mirror B, the victim would be filled with lu** for the offender. And if the victim already has someone they love, the part of their consciousness that loves this person will be trapped in the mirror and these memories will be replaced by the new ones by the mirror to manipulate the victim to believe that they are in love with the offender instead
There are two mirrors (let's say A and B). The mirror A will be given to the victim by the offender who keeps the mirror B with themself. If the victim was to look at mirror A while the offender is facing the mirror B, the victim would be filled with lu** for the offender. And if the victim already has someone they love, the part of their consciousness that loves this person will be trapped in the mirror and these memories will be replaced by the new ones by the mirror to manipulate the victim to believe that they are in love with the offender instead