I really need to start exercising but have a really hard time staying committed to anything. So how can I keep myself motivated to exercise??

*and also, will exercising make dark circles under my eyes go away?

I hate doing exercise too. But for me it's easier to do a sport. Sports like swimming, roller blading, ice skating, tennis, soccer, etc can be really good exercise if you take lessons and do them a few times a week. When you do something like this it doesn't feel like exercise it is fun and keeps you interested in doing a sport you can get better at.

Group-oriented exercises were made for people just like you. Have you thought about joining a local fitness class, or even a dance class or something like it?

If the "exercise" becomes a fun social event instead, you won't mind doing it so much.

After that, the RESULTS you generate are what will keep you motivated.