I already know the answer. The love potion had to be used at the start of the game because I was trying to replay it. And the mission was listed as completed. I was very sad that I had to go back and start over again.
My success didn't progress. I used love potions with a girl whose relationship rating was less than 100. I have used it but my success is not considered successful. Did I miss something?
Next update I would like to show you all missions to complete, how to choose missions. It will be easier I don't want to wander around the continent to find out which one has a mission. Mark this person as having a mission to do. Thank you very much.