"well-being," Old English wela "wealth," in late Old English also "welfare, well-being," from West Germanic *welon-, from PIE root *wel- (2) "to wish, will" (see will (v.)). Related to well (adv.).
Entries linking to weal
Old English walu "ridge, bank" of earth or stone, later "ridge made on flesh by a lash" (related to weal (n.2)); from Proto-Germanic *walu- (source also of Low German wale "weal," Old Frisian walu "rod," Old Norse völr "round piece of wood," Gothic walus "a staff, stick," Dutch wortel, German wurzel "root"), from PIE root *wel- (3) "to turn, revolve." The common notion perhaps is "raised line." Used in reference to the ridges of textile fabric from 1580s. Wales "horizontal planks which extend along a ship's sides" is attested from late 13c.
The Germanic words are from PIE root *wel- (2) "to wish, will" (source also of Sanskrit vrnoti "chooses, prefers," varyah "to be chosen, eligible, excellent," varanam "choosing;" Avestan verenav- "to wish, will, choose;" Greek elpis "hope;" Latin volo, velle "to wish, will, desire;" Old Church Slavonic voljo, voliti "to will," veljo, veleti "to command;" Lithuanian velyti "to wish, favor," pa-velmi "I will," viliuos "I hope;" Welsh gwell "better").
Compare also Old English wel "well," literally "according to one's wish;" wela "well-being, riches." The use as a future auxiliary was already developing in Old English. The implication of intention or volition distinguishes it from shall, which expresses or implies obligation or necessity. Contracted forms, especially after pronouns, began to appear 16c., as in sheele for "she will." In early use often -ile to preserve pronunciation. The form with an apostrophe ('ll) is from 17c.