Which one do you prefer for a girl? And no, we don't really mind pronunciation issues or the fact people won't be able to say them. If people can learn to say Schwarzenegger I'm sure they can say either of these names.
Xiomara is pronounced like see-oh-mara
Ximena is he-meh-nah
It would be an average British surname with easy pronunciation. I am Colombian and DH is British and we live in the UK.