fainest

adverb

1. gladly; willingly: He fain would accept.

adjective

2. content; willing: They were fain to go.
3. Archaic. constrained; obliged: He was fain to obey his Lord.
4. Archaic. glad; pleased.
5. Archaic. desirous; eager.

adverb

1. (usually with would) archaic willingly; gladlyshe would fain be dead

adjective

2. obsolete
   1. willing or eager
   2. compelled

adj.

Old English fægen, fagen “glad, cheerful, happy, joyful, rejoicing,” from a common Germanic root (cf. Old Saxon fagan, Old Norse feginn “glad,” Old High German faginon, Gothic faginon “to rejoice”), perhaps from PIE *pek- “to make pretty.” As an adverb, from c.1200.