After the second popstar mission, Amanda will appear outside your apartment. Take her on a brief tour of the city (Bam Bam Club and the Temple), ending at the martial arts dojo. Complete the training exercise to finish the mission. You will then be able to call her for a proper date. Successfully complete the date with Amanda (where you take photos of her) to have unclaimed Health Shrines appear on the mini-map. For every five health shrines you collect, your max hit points will be increased by 10%.