ensure, check, secure, insure, see to it, see, hearten, tell, control, guarantee, encourage, assure, ascertain, promise, give confidence.
You can reassure
yourself on that point.
She tried to reassure
herself by recalling all that gentle Mrs. Martin had said, but as the moments passed, her apprehension grew, and when she tried to eat, the food almost choked her.
None the less, he was careful to reassure
her wholly by the announcement of his discovery of the important nature of the evidence he could give, before he said anything about those articles.