You are not forced to like them!
Viewing post in Hero's Harem Guild (NSFW +18) comments
well... not in irl way, but in the gameplay way you must like all of them to move the story. if the requirement for quests was a total of levels among girls like "get x levels among 'paste list of girls that count here' " or "get to minimum level x with at least y girls" then you would either level all of them up because you wanted to or just pick a couple. more freedom for the player :)