Whether you think you will succeed or not, you are right.
If you think you can do a thing or think you can't do a thing, you're right.
I didn't get much peace, but I heard in Norway that Russia might well become a huge market for tractors soon.
Some people think they can; some think they can't. They are probably both right.
The farther you look back, the farther you can look ahead.
Whether you believe you can or not, you're right.