How should i understand:"I just want to be sure of you."?
“Piglet sidled up to Pooh from behind. "Pooh," he whispered.
　　"Yes, Piglet?"
　　"Nothing," said Piglet, taking Pooh's paw, "I just wanted to be sure of you."”

Question

How should i understand:"I just want to be sure of you."?
“Piglet sidled up to Pooh from behind. "Pooh," he whispered. 
　　"Yes, Piglet?" 
　　"Nothing," said Piglet, taking Pooh's paw, "I just wanted to be sure of you."”

Answer

He wanted to be sure if Pooh was still there , and from now on he is going to hold Pooh's paw to avoid wondering the same thing again, because now Piglet is feeling his friend ... aaawwwww

Answer

just wanted to feel his presence or get close (due to instant feelings of   fear or alone or love or any unmentionable/personal thinking)

Answer

Piglet is saying that he wants to make sure Pooh is safe.
In actuality, Piglet is frightened and taking Pooh's hand, but is embarrassed to admit his fright.