keep one's chin up
همچنان امیدوار و مثبت فکر کردن

طرف از یه چی ناراحته میخوای بگی " بابا بی خیال......"

to stay positive

EXAMPLE 1: Even when he was unemployed and homeless, Bill managed to keep his chin up.

EXAMPLE 2: Keep your chin up! You'll find your lost dog soon