First of all, you can search on Comprehensive 360, which contains many famous American sayings. Here I can offer you some:
The sun will rise tomorrow. The sun will rise again tomorrow.
Dream more when you are awake.
When you are not sleeping, dream more!
Smile more.
Smile more, smile more!
Your heart is the happiest. So, be happy.
Your heart is always happy! So be happy!
No one is responsible for your happiness except yourself.
No one can control your happiness, only you!
Don't have negative thoughts about things that are beyond your control. Instead, put your energy into the positive present.
Don't have negative thoughts about things beyond your control. Instead, focus on the positive present.
Realize that life is a school where you study. Problems are only part of the course, appearing and disappearing, but the lessons you learn will last a lifetime.
Realize that life is a school. The problems you encounter are only part of your course. Problems will appear and disappear. However, the lessons you learn from it will benefit you for life.
Throw away anything that is useless, unattractive or unhappy.
Throw away all those useless, unattractive and unpleasant things!