To make certain that something will occur or be the case.

To guarantee or secure.

गारंटी देना

English Usage: They want to ensure their investment is safe.

Hindi Usage: वे यह गारंटी देना चाहते हैं कि उनका निवेश सुरक्षित है।

A promise or guarantee (less common usage).

वादा या गारंटी

English Usage: The ensure of safety was his priority.

Hindi Usage: सुरक्षा का वादा उसका प्राथमिकता था।