...say you're scared.
It's more honest and accurate.
You should be naturally demotivated to do things you don't want to do, but you can't claim demotivation on things you desire.
No, that's just fear.
1. You have a fear of failure, success, uncertainty, etc.
2. You don't love and believe in yourself
3. You don't know how to be perfect
4. You don't know how to fail well
5. You're scared of what others may think
But you're not demotivated!
Once you call a spade a spade and own the reality of your situation, then you can begin exerting the right effort.
"Courage is resistance to fear, mastery to fear, not absence to fear." Mark Twain