This door will open only to those who don't care about their looks . First you have to put on some weight. Move to Brightwall and drink all the beer in the pub and eat mutton at the nearby market. Just approach the chosen item, buy it and choose to eat/drink once it starts floating above your head. Repeat the process several times. If the shops run out of goods, go to sleep and a supply will arrive in the morning. Once you're gat enough, it's time to choose a proper dress. Change into pyjamas in the Sanctuary, dye it brightly and get rid of all tattoos. Looking like that, stand in front of the door and wait for it to open .