Saul knew there would never be a Sam Vimes who would consent to becoming Sam Ramkin. That just was not Sam's way. It didn't bother Saul. So Sam kept her name after they married.
But there may be children one day, so Saul mused on it, and one day six months after they were married, Saul surprised Sam at the Pseudopolis Watch House with lunch and something else.
"I went by my solicitors today," Saul said, looking at the love of his life tear through the sandwich he had made for her. "I was thinking about…children. Maybe. One day. And I thought about you and me and…"
Saul was unusually tounge-tied and Sam was giving him an odd look, so Saul just showed her the paper declaring that Lord Saul Ramkin was now Lord Saul Ramkin-Vimes.
"Any kids we have, they'll be Ramkin-Vimes. Any children they have will be Ramkin-Vimes. There is no just 'Ramkin' after you and I, it will be 'Ramkin-Vimes' after this." He smiled at Sam's flabbergasted look. "Honestly Sam, you turned my life around, and what better way to show it than this?"
Samantha Vimes was not one for public affection, but she made an exception and proceeded to snog the hell out of her husband.