willingly
willingness
willing | American Dictionary
willing
adjective
us/ˈwɪl·ɪŋ/
not opposed to doing something; ready or eager to do something:
If you’re willing to fly on Thursday you can get a cheaper ticket.
willingness
noun[ U ]us/ˈwɪl·ɪŋ·nəs/
She shows a willingness to work hard.