1. I know you can do it.
2. I have confidence in your abilities.
3. I have faith in you.
4. I believe in you.
5. I trust you.
= I believe that you are honest and loyal.
6. I respect you.
= I have an appreciation for your value or behavior.
7. I admire you.
= I believe that you have a lot of strengths.
= I admire the thing that you have achieved in your life.
8. I love you.
(You can say that to a spouse / partner, family members and friends.)