If someone is very willing to do something, you can talk about their readiness to do it.
//…their readiness to co-operate with the new US envoy.
他们乐意和新任美国特使合作
~ (of sb) (to do sth) the state of being willing to do sth 愿意；乐意
Over half the people interviewed expressed their readiness to die for their country.
半数以上受访者表示愿意为国献身。