You have to accept their love, otherwise they may force you to do it.
>Say no to Mewtwo, get mindraped as a response
>Say no to Salazzle, have your senses be clouded by her pheromones, enthralling your will to hers
>Say no to Serperior, coiling by the snake or subdued with vine whips
Just smile and nod your head when she asks you for something intimate