If I was going to shorten Cynric and "Rick" was out of the question, I'd probably go with Ken, since some anglicisations of Cynric turn it to Kenrick. It's not quite the same sound, but it's close and it's better than fucking Sin.

She seriously pronounces them like that? My head hurts. I don't usually make fun of people for not being able to pronounce words properly, because god knows I remember what it was like being a teenager with a wide vocabulary that I'd gained from books and not actually knowing how some of those words were pronounced, but this is a professional writer and those words aren't exactly unusual.