Cause to feel sure; give reassurance to:
— The airline tried to reassure the customers that the planes were safe.

synonym: assure.

Roget 858: hope, trust, confide, rely on, put one's trust in; lean upon; pin one's hope upon, pin one's faith upon etc. (believe) 484.    feel hope, entertain hope, harbor hope, indulge hope, cherish hope, feed hope, foster hope, nourish hope, encourage hope, cling to hope, live in hope, etc. n.; see land; feel assured, rest assured, feel confident, rest confident etc. adj.. presume; promise oneself; expect etc. (look forward to) 507.    hope for etc. (desire) 865; anticipate.    be hopeful etc. adj.; look on the bright side of, view on the sunny side, voir en couleur de rose [Fr.], make the best of it, hope for the best; put a good face upon, put a bold face upon, put the best face upon; keep one's spirits up; take heart, take heart of grace; be of good heart, be of good cheer; flatter oneself, lay the flattering unction to one's soul," catch at a straw, [Hamlet], hope against hope, reckon one's chickens before they are reckon one's chickens before they are hatched, count one's chickens before they are hatched.    [cause hope] give hope, inspire hope, raise hope, hold out hope etc. n.; promise, bid fair, augur well, be in a fair way, look up, flatter, tell a flattering tale; raise expectations (sentient subject); encourage, cheer, assure, reassure, buoy up, embolden.    ... show more

Roget 861: be courageous etc. adj.; dare, venture, make bold; face danger, front danger, affront danger, confront danger, brave danger, defy danger, despise danger, mock danger; look in the face; look full in the face, look boldly in the face, look danger in the face; face; meet, meet in front; brave, beard; defy etc. 715.    take courage, muster courage, summon up courage, pluck up courage; nerve oneself, take heart; take heart, pluck up heart of grace; hold up one's head, screw one's courage to the sticking place; come up to scratch; stick to one's guns, standfire^†, stand against; bear up, bear up against; hold out etc. (persevere) 604.1. put a bold face upon; show a bold front, present a bold front; show fight; face the music.    bell the cat, take the bull by the horns, beard the lion in his den, march up to the cannon's mouth, go through fire and water, run the gantlet.    give courage, infuse courage, inspire courage; reassure, encourage, embolden, inspirit, cheer, nerve, put upon one's mettle, rally, raise a rallying cry; pat on the back, make a man of.   , keep in countenance.    ... show more

Give or restore confidence in; cause to feel sure or certain.