Synonyms for Make certain:

• v.

  •ascertain (verb)
  • find out,
  • fix,
  • determine,
  • verify,
  • see,
  • make sure,
  • settle,
  • establish.
  •ensure (verb)
  • clinch,
  • effect,
  • certify,
  • warrant,
  • nail down,
  • insure,
  • secure,
  • cinch.
  •guarantee (verb)
  • guaranty,
  • stand behind,
  • ensure,
  • affirm,
  • vouch for,
  • reassure.

• Other synonyms:

  •
  • assure.
  •
  • confirm.
  •make sure
  • ascertain.
  •Other relevant words:
  • pick,
  • be sure,
  • get at,
  • agree,
  • mind,
  • decide,
  • pledge,
  • see to it,
  • set,
  • be certain,
  • swear to,
  • sort out,
  • ensures,
  • stabilize,
  • choose,
  • attest to,
  • be vigilant,
  • be confident of,
  • set at rest,
  • convince,
  • appoint,
  • settle upon,
  • guarantee,
  • conclude,
  • persuade,
  • undertake,
  • settle on,
  • promise,
  • clear up,
  • make sure of,
  • satisfy,
  • select,
  • warranty.

Antonyms for Make certain:

• v.

  • ascertain
    help, unsettle, assist, aid, confuse, invalidate, neglect, overlook, miss, misunderstand, destroy, disprove, look away, ignore.
  • ensure
    endanger, injure, forget, deny, repudiate, reject, hurt, veto, harm, contradict.
  • guarantee
    let go, oppose, refute, discourage, break.
  • mind
    disregard, obey, disobey.
  • settle
    disorganize, derange, hesitate, owe, disagree, refuse, depart, leave, trouble, begin, move, lose, mix up, mismanage, disarrange, upset, disorder, commence, start, worry, disturb.
  • verify
    discredit, hide, conceal.