IPA: /mɛˈlɪf.lu.əs.nəs/
KK: /mɛˈlɪf.lu.əs.nəs/
The quality of having a smooth, pleasant sound that is sweet and soothing to hear.
The mellifluousness of her voice captivated everyone in the room.
Mellifluousness → It is formed from "melli-" (from Latin "mel", meaning honey) and "fluere" (meaning to flow), combined with the suffix "-ous" (meaning full of) and "-ness" (indicating a state or quality). The word describes a quality of having a smooth, sweet flow, akin to honey flowing.
Think of 'honey' ('melli-') flowing smoothly ('fluere') to remember that 'mellifluousness' refers to a sweet, smooth quality.
No commonly confused words.