I usually pronounce it as "wanov" but not sure if it's the correct pronounction and need some clarification.
Thanks in advance.
Americans are very likely to drop the v sound if the next word begins with a consonant. The result is more like wunnuh.
If the next word begins with a vowel, as in "one of a kind", I don't think we're as likely to drop the v. So the result is more like wunnuv.
"wun-uv" or "wun-nuh" depending on the dialect.