1) Cheerfully 2) Eagerly 3) Enthusiastically 4) Freely 5) Gamely 6) Gladly 7) Happily 8) In a willing manner 9) Of your own accord 10) Of your own free will 11) One way to comply 12) Readily 13) Volitionally 14) Voluntarily 15) With good grace 16) With joy 17) With pleasure 18) Without reluctance 1) Fain 2) Gladly 3) Keenly 4) Lief 5) Volitionally 
• (adv.) In a willing manner; with free will; without reluctance; cheerfully.
Will'ing·ly adverb In a willing manner; with free will; without reluctance; cheerfully. Chaucer. « The condition of that people is not so much to be envied as some would willingly represent it.» Addison. 
[adv] - in a willing manner
volitionally adverb in a willing manner; `I willingly accept`