I wouldn't go with Charlotte Rarity; I think Rarity is a perfectly fine name! Seriously, I'm not joking. A lot of people now will tell you it's a bad idea and it will lead to the child being bullied or teased. This is ridiculous; there is a chance that your kid will get teased for her name no matter what name you give her unless it's something really really common and plain, but if you don't want to go with a plain, boring name, then so long as the name isn't REALLY out there, I don't think an unusual name like "Rarity" is a problem. Here's what happens when people find out someone's name is really unusual and something they haven't heard before: they think it's weird at first, for the first little bit, but very quickly after getting to know the person they'll associate the name with the person. So when they hear "Rarity" they won't think "that's an unusual name," they'll instead think of that girl, because they've associated the name with her in their minds. This is of course all assuming that the person isn't familiar with MLP. If they are, then they might think of the pony at first before associating the girl with the name. They also might think it's really weird that you named a kid after a pony. But there's only going to be a few people who think that, and who cares what they think! The vast majority of people who hear your girl's name will either not be familiar with MLP and think "that's an unusual name" at first, until they get used to it, which will not take very long, trust me, or they will be familiar with the show and think it's really cool that you named a kid after one of the characters or they'll think it's weird but they won't care after they get to know how awesome and cool your kid is (assuming she turns out to be awesome and cool). So try suggesting just "Rarity" to your girlfriend. See if she likes it. If not, maybe see if you can get her to accept it as a middle name.