Are dELiAs jeans comfortable?

Yes!!! I have the EXACT same problem. You see, both my parents are from northern Germany, so I'm pretty tall. This is actually really cool, I don't know many other girls who are 5'8 but not pencil thin hahha. The good thing about Delias is that they have long jeans, which is what I always get. Generally they're sized with two sizes so I would recommend that you try either a 3/4 long or a 4/5 long. Honestly, I find them amazingly comfortable, also because they're not too loose to the point that they're unflattering. They're comfy but they still kind of hold everything in (if you know what I mean lol) and make your legs look longer. Since you're tall too I'm guessing you also have an obsession with longer thinner legs. Just try it out, I love them!