Wǒmen zhēnxīnchéngyì de xīwàng hézuò néng gòu chénggōng.
We sincerely hope that the cooperation will succeed.
Tips
usage
真心诚意 is often used adverbially before a verb, with 地 (de) in between: 真心诚意地 + verb. It emphasizes both emotional sincerity (真心) and moral integrity (诚意).