The proprietor of the now-hotel Vault 21, Sarah Weintraub, wishes to restock her supply of Vault suits, which are highly sought-after collectors items, especially among the wealthy visitors that come to visit the Strip and stay at her hotel. However, she has burned through her stock of Vault 21 jumpsuits and needs spares to sell. The player can offer to be on the lookout for them.
Sarah will not purchase any Vault 21 jumpsuits, but will accept any of the following:
Vault 3, 11, 22, and 34 jumpsuits, found at their respective locations. She pays 30 caps per suit.
Each sale also increases the Strip positive reputation and gives the player a discount on renting the Vault 21 hotel room. After delivering 30 Vault suits (not Boomer suits) in total, Sarah will mention missing the Courier when they're away. The player can flirt with her, which ends up with Sarah suggesting to "catch up" in her quarters. It's also possible to flirt with her more directly (Speech 50 and 75 checks), which will result in Sarah deciding to have casual sex when the player brings back any Vault suit.
Note that in order to sleep with Sarah, the player has to go down into the hotel and enter their room. Sleeping with her grants the Well Rested bonus, giving 10% bonus XP, but does not reduce Sleep Deprivation in Hardcore mode.
This includes any vault jumpsuits that the player can scavenge. She will accept jumpsuits from any of the in-game vaults, except for suits stolen from the guest rooms in Vault 21. With a Barter check of 65, she will accept Boomer jumpsuits and Boomer flightsuits.
The reward will be caps, Strip reputation, and a discount on the Vault 21 guest room. After you bring her 30 Vault suits of any kind, on your next visit she'll mention missing the player character. You will then be able to have sex with her as you both "catch up" with one another, which gives the Well Rested bonus (which is not earned by sleeping in Vault 21's guest room). Also, after two Speech checks, 50 and 75 respectively, she will agree to having sex after receiving suits, along with accepting Boomer suits.