Hello!
The Cute Sandals are in a little red box on a shelf in the locked room of the Brothel's second floor (Bottom Left Room). You don't need to work in the Brothel to get it. There are two ways of going about it. You can either Pick the Lock on the door and take them out of the box. Or you can use the Vines outside to Climb in through the Window into that room, then Climb out through the same Window once you got them. Neither of the approaches have any negative repercussions, it just depends on whether you have a Skill for Climbing or Lockpicking. If you have neither skill then you will need to get the skills for it first. There is a Quest in the Goblin Tower that awards Athletics which has the Climb specialisation. And Guile can be purchased of the Skill merchant on the second floor of the Brothel on the Weekends, Guile has the Lockpicking specialisation.