make certain

Remove all doubt

To make certain is to ensure something happens or verify that it has: Make certain you lock the door before leaving.

The phrase emphasizes taking deliberate steps to confirm or guarantee an outcome, slightly more emphatic than simply checking: I called ahead to make certain they had our reservation.

confirm

verify

Confirm accuracy or truth

validateConfirm as true
corroborateConfirm with supporting evidence
substantiateProve something is true

authenticate · prove · check · establish · demonstrate · determine · affirm · attest · document · cross-check

guarantee

ensure

Make something definite

secureProtected from harm
assurePromise with confidence
promiseCommitment to act

pledge · warrant · safeguard · protect · underwrite · insure · commit · vow · seal · clinch

reassure

assure

Promise with confidence

comfortEase or soothing relief
convinceCause to believe
satisfyMeet a need fully

put at ease · calm · relieve · soothe · encourage · hearten

Opposites

epistemic certainty

make certainassume

Accept as true

presume · take for granted · leave to chance · guess · suppose

intentional action toward outcomes

make certainneglect

Failure to provide care

leave to chance · risk · overlook · ignore · gamble

Family

make, certain, makes, made, making, maker, makers, remake, remaking

Familiarity: Top 50,000
Profile: Known to kids · Used worldwide · Timeless · Abstract · Everyday, not technical · Rated G