Pronunciation guide: IPA symbols, stress and word endings

θ	thin	ð	this	ʃ	she	ʒ	measure
tʃ	church	dʒ	judge	ŋ	sing	j	yes

p b t d k g f v s z h m n l r w sound as in ordinary English spelling.

ˈ main stress, before the stressed syllable: /ˈwɔːtə/ water · ˌ lighter (secondary) stress: /ˌʌndəˈstænd/ understand
ː a long vowel · (r) an r said only in accents that pronounce it (most American, Scottish, Irish)

-s / -es (plurals; he/she form of verbs): /s/ after voiceless sounds (cats), /z/ after voiced (dogs), /ɪz/ after s, z, sh, ch, j sounds (buses, watches). Spelling: -es after s, x, z, ch, sh; consonant + y → -ies (city → cities).
-ed (past): /t/ after voiceless sounds (walked), /d/ after voiced (played), /ɪd/ after t or d (wanted). Spelling: love → loved, stop → stopped, carry → carried.
-ing: make → making, run → running, see → seeing.
Irregular: go, went, gone · be, was, been · see, saw, seen · man → men · child → children · mouse → mice.
Older (King James) forms: -eth = -s (he loveth = he loves) · -est with “thou” (thou lovest) · spake = spoke.

ensure

/ɪnˈʃʊɹ/ verb

Forms ensures ensuring ensured

verb (intransitive) To make sure or certain of something (usually some future event or condition). “I use an alarm clock to ensure that I get up on time.”
verb (transitive, obsolete) To make a pledge to (someone); to promise, guarantee (someone of something); to assure.

Synonyms

From Middle English ensuren, from Anglo-Norman enseurer, from Old French seur (“sure”). Doublet of insure.

Sources: Wiktionary · WordNet 3.0 · Webster’s 1913 — from the Wiktionary entry “ensure”, CC BY-SA 4.0. Details

Sanskrit dictionary entries whose meaning includes “ensure” (best matches first).

गर्भाधान garbhādhāna impregnation; a ceremony performed after menstruation to ensure or facilitate conception.