By the Magic E rule, the ending -ONE should always rhyme with bone. And most of the time it does. But four of the most common words in English refuse: done, none, one, and gone. Knowing exactly which words break the rule is the whole battle.
The Rule
Default: -ONE = /oʊn/. The silent E makes the O long, so these rhyme with bone: phone, stone, zone, tone, cone, alone, throne, ozone, hormone, telephone. This is your safe assumption for any new word.
Exception A: /ʌn/. Three high-frequency words say the short-U sound: done and none rhyme with fun, and one is /wʌn/ (with a hidden W at the front, exactly like won).
Exception B: /ɔːn/ (or /ɒn/). The word gone has a short "aw/o" vowel; it rhymes with on, not bone.
Practice Words
The Compound Trap
Because one is /wʌn/, every word built from it keeps that sound: someone, anyone, everyone, no one all end in /wʌn/, never /woʊn/. One more curiosity: scone is accepted both ways, /skoʊn/ (rhyming with bone) and /skɒn/ (rhyming with on), depending on the speaker. Outside these, trust the /oʊn/ default.
Quick Tip
Memorize the rule-breakers as one short sentence: "One is done, none is gone." Those four are the exceptions; if a -ONE word is not in that sentence, say it like bone.