않믿어요 -> i think it means 'i don't believe it or sth' but it's grammatically wrong. it should have been written '안 믿어요. (or 믿지 않아요.) and.. 믿고 안믿고 휴일날 가족끼리 화목하게 저녁먹는건데.. someone wrote this as the answer of '안 믿어요'? then.. it could mean 'whether you believe or not it's a harmonious dinner with family on holiday...' actually i want to know the exact situation though :P i hope this will be helpful for you!

안녕하세요!~