I like the way they sound together, but the fact that they both end in “the” and are pronounced differently, would that cause issues?
I know they’re very different styles, but what I’m most worried about is that people would look at how [name_f]Blythe[/name_f] is pronounced and try to do the same pronunciation for [name_f]Xanthe[/name_f]…change it from [name_m]Zan[/name_m]-thee, to Zanth.
What do you think?
The only thing that would give me pause would be that they’re so different stylistically, not that the ends are pronounced differently. If anything, the ends being pronounced differently seems like a cool opportunity for teaching them about linguistic differences. I’m sure a lot of people would be puzzled by how to pronounce [name_f]Xanthe[/name_f] even if she didn’t have a sister named [name_f]Blythe[/name_f].
I don’t think that would present any difficulty at all - that the endings were the same didn’t even occur to me until you pointed it out! For what it’s worth, I love [name_f]Xanthe[/name_f] and [name_f]Blythe[/name_f] together.
I think they are nice together. As oregano7 mentioned, a lot of people may be puzzled by how to pronounce [name_f]Xanthe[/name_f] even if she didn’t have a sister named [name_f]Blythe[/name_f]. That’s only because it isn’t a common name, but it is lovely and I think, worth the effort to gently correct anyone that mispronounces her name. Most people will just ask.
My first thought upon seeing them together was that they look great together. I didn’t notice that they both ended in -the until you drew my attention to it. Now having had a moment to think about it, I feel like while [name_f]Xanthe[/name_f] and [name_f]Blythe[/name_f] are extremely different stylistically, the repeated -the, actually brings them together to fit with one another beautifully. I like that they end the same way, yet sound different, and I also like that they both share letters – X & Y – that have (what I like to call) punch and give the names a bit of kick.
As for the pronunciation of [name_f]Xanthe[/name_f], regardless of the fact of whether she had a sister [name_f]Blythe[/name_f] or now, there would certainly be people that did not know how to pronounce the name. I don’t think that’s a big deal though – all it takes is a quick correction, and most people will get it right from there on out.
I adore both [name_f]Xanthe[/name_f] and [name_f]Blythe[/name_f] - they’re gorgeous names.
I wholeheartedly agree with this. I actually found the -the ending binding for two very stylistically different names. As @sunniva and others have said, [name_f]Xanthe[/name_f] is likely to give pronunciation issues regardless of whether or not she has a sister named [name_f]Blythe[/name_f]. If you’re okay with that, they make a lovely sib set!
They look great together, but I don’t know how to pronounce the actual names 
I think they sound good together, but I knew what your issue was immediately after seeing the title, and I do think it would be confusing to people, considering they look kind of similar but have very different backgrounds and pronunciations. Many people don’t know what ‘blythe’ means anymore, don’t know it’s an adjective, don’t use it in everyday speech; the pronunciation of [name_f]Xanthe[/name_f] is unclear to most people who see it the first time.
I don’t think it’d be a serious issue, as siblings and mothers have gotten along just fine in situations worse than this, but I do think it could be a minor point of frustration and confusion for you, your children and people you come into contact with. A simple explanation should be enough, but you’ll have to give that explanation over and over again. It won’t be so bad if you don’t expect people to get it right the first time.
However, if you’re already worried about it now, and you don’t have any children, I’d just say that [name_f]Xanthe[/name_f] and [name_f]Blythe[/name_f] can stay on your list, but they have to be mutually exclusive.