“Necessarily” is a B2 level adverbs that is used in negatives to mean ‘in every case’ or ‘therefore’.
We didn’t (4)…… want to go, but we felt like we had to.
Examiner: “Some people say we need to eat less meat to improve our health. What do you think?”
Candidate: “I don’t think that’s necessarily true, it depends on what you are replacing the meat with…”