Some clematis are more susceptible to wilt than others. Niobe is one that is quite susceptible in my garden. It won't spread wilt to other plants. It may outgrow it eventually, especially if you plant it so the base of the plant is buried 4" or so deep. Be sure it gets even moisture throughout the growing season, and it will probably appreciate a couple of inches of mulch, though keep mulch away from the stems. If you move it, hard prune it. You can also prune any stems that are developing wilt any time during the growing season. Not enough sun won't cause wilt, but it may grow and bloom better in a spot that has more sun.

My Niobe in 10 years or so has never given me more than about 4 flowers a year, and some seasons it gets wilt, though it didn't this year. I have it planted in a spot that there's a rose and a metal trellis it can climb if it wants to, but in years that it doesn't do well it is fairly well hidden by plants in front of it.