Collins Chinese Dictionary Plus (3rd edition), 2011:
郑(鄭)
zhèng
郑(鄭)重 zhèngzhòng 形
serious
- 对(對)方郑(鄭)重表示愿(願)意与(與)我们(們)合作。 Duìfāng zhèngzhòng biǎoshì yuànyì yǔ wǒmen hézuò. The other party is expressing a serious desire to work with us.