I'm studying English and I'm reading a book how to improve your English. The writer said that those who study English should approach foreigners to improve English. After that, he write:
Most students do not dare to approach foreigner at all, often because they are afraid to look like an idiot. Their confidence is too low to handle the uncertainty of not being convinced that they know everything they ought to do and say, and they have such low regard for themselves. However, it is much better to take action and risk looking like an idiot with a chance of improving your English than not to take action and clearly demonstrate that you are an idiot with no chance of improving your English.
I know "uncertain" means "not sure", and "convinced" means "completely sure about something",but I still don't understand the sentence, especially the expression "handle the uncertainty of not being convinced that". Can you help me? Thank!