Here are some synonyms for reluctantly:
* Unwillingly
* Hesitantly
* With hesitation
* Against one's will
* With misgivings
* Grudgingly
* With a heavy heart
Example:
* "She reluctantly agreed to go to the party, knowing she would be bored."
* "He reluctantly gave up his seat on the bus to an elderly woman."
In contrast, someone who does something willingly would do it enthusiastically or eagerly.