[Kransha]

Well, I do not believe this belongs in this forum, but I'll answer it.

The names weren't just made up (well, I suppose they were), but they mean something. Some names are similar simply coincidentally, like these. The meaning are all different, and in different tongues, so the resemblance of names is technically irrelevant. I personally think that 'Eowyn' and 'Arwen' sound very different and look very different, though Saruman and Sauron are a bit similar. Here are the name meanings, as I know them.

Sauron: "The Abhorred" (Sindarin, I believe: This one's a bit tricky, because J.R.R. never gave us a meaning. Christopher Tolkien, using the name 'Tauron' [Another name for Oromë, meaning 'Lord of Forests') translated Sauron as, "Lord of Abomination". Thus, Sauron can be translated as, Lord of Abomination or Abhorrent One, or Abominable One, or what have you)
Saruman: "Man of Skill" (Again, Sindarin: This, though, I am unsure of. Like all the Maiar, Saruman is known by many other names, like Curunir and Curumo, both of which have something to do with being 'skillful')
Arwen: "Noble Maiden" (Sindarin)
Eowyn: "Horse-joy" (Rohirric: The tongue of Rohan, which has some very definitive roots in Olde English)