nec·es·sar·i·ly 
/ˌnɛsəˈserəli/ adverb
/ˌnɛsəˈserəli/ adverb formal — used to say that something is necessary and cannot be changed or avoided ▪ This endeavor necessarily involves some risk.
not necessarily
: possibly but not certainly — used to say that something is not definitely true ▪ Seats in the front row are not necessarily the best. ▪ “We're going to lose this game.” “Not necessarily.” [=maybe not]
