Oh, they skipped the part where Touka destroys the inn's wall by buffing Pigimaru up!
Touka is genuine on wanting Seras' help, even if so far it's always him saving her arse. It's less as a bodyguard though and more like a walking lie detector.
As well as the similarity that Seras sees between the Princess and Touka - unlike other people, they're looking at what she can do for them, not just for her beauty. So far the anime did a poor job explaining it, but Seras is in-world so beautiful that she drives people mad lusting over her.
Telling Seras to take off her clothes is not in the manga. I wonder if it's from the LN or anime only. Kind of cringe but still funny.