My best friend's name is Cosmina, it's a beautiful name. I don't really get people who think it's funny, but this is just my opinion. And please don't say it's ugly sounding. It's beautiful.
I was never fond of this name until a dream I had. So, of course, I came here to look it up and saw that it sadly had no comments. :( I believe this name is really pretty. I wouldn't use it in real life but I definitely would name a character Cosmina. There are a lot of cutie pie nicknames available, too. Cosma Cos Mina Minnie Mouse (all right, maybe not really but it'd still be adorable for a silly nickname)