Actions speak louder than words

I don't believe you when you say you can complete your assignment in a couple of hours
I don't believe you when you say you can cook XXX dish
I don't believe you when you say YYY happened to you when you were young
I don't believe you when you say you have that much self control
I don't believe you when you say you can fly
Prove it to me, and I'll know you didnt lie...