“Sounds Good” Means “That Plan Works for Me”

“Sounds good” commonly accepts a suggestion or arrangement; it is not necessarily a comment about sound. It is close to “That plan works for me”, more neutral than “That’s a great idea”, and slightly more positive than a bare “OK”.

For example: “I’ll meet you outside the station at six.” “Sounds good. See you then.” The reply confirms the arrangement. Said on its own with a flat tone, “Sounds good” can also be no more than polite acceptance; adding “See you then” makes the commitment clearer.

Chinese speakers do not always need to translate it literally as “听起来很好”. When arranging a time, choosing a restaurant or dividing up work, it is more natural to understand it as “That arrangement works for me”.

Sources: https://dictionary.cambridge.org/dictionary/english/sound; https://www.oxfordlearnersdictionaries.com/definition/english/sound_3