Present Tense Affirmations 
I am strong against negative life circumstances 
I can face anything that confronts me
I am prepared for life
I face life head-on
I trust myself with everything
I have full confidence in myself
I am bold and brave
I have willpower
I am in control of my life
I use my inner strength in necessary situations

Future Tense Affirmations 
I will stop being soft 
I will focus on building my inner strength
I will harden my emotions
I will practice using my inner strength
I will protect myself against hurt
I will learn to shield myself from pain
I will stop being weak
I will have a strong guard against outside influence
I will harden my personality
My inner strength will be reliable

Natural Affirmations
I am naturally strong
I was born with inner strength
I just have a natural inner hardness
I am simply protective of my feelings
My natural personality shines
I have full faith in myself
I believe in myself
My opportunities are unlimited
I can stand up to anything
Others see me as a strong, independent individual