"dearly, gladly, willingly" (obsolete or archaic), c. 1250, from Middle English adjective lief "esteemed, beloved, dear," from Old English leof "dear, valued, beloved, pleasant" (also as a noun, "a beloved person, friend"), from Proto-Germanic *leuba- (source also of Old Norse ljutr, Old Frisian liaf, Dutch lief, Old High German liob, German lieb, Gothic liufs "dear, beloved"), from PIE root *leubh- "to care, desire, love."
Often with the dative and in personal constructions with have or would in expressions of choice or preference (and yet, to say the truth, I had as lief have the foppery of freedom, as the morality of imprisonment; "Measure for Measure"). I want and I'd love to are overworked and misused to fill the hole left in the language when I would lief faded in 17c.
"sweetheart, paramour, loved one" (archaic), c. 1200, lemman, "loved one of the opposite sex; paramour, lover; wife;" also "a spiritually beloved one; redeemed soul, believer in Christ; female saint devoted to chastity; God, Christ, the Virgin Mary;" also a term of intimate address to a friend or lover, contracted from late Old English leofman, a compound of leof "dear" (see lief) + man "human being, person" (from PIE root *man- (1) "man").
Originally of either gender, though in deliberate archaic usage it tends to be limited to women. Often in religious use in early Middle English, of brides of Christ, the spiritually beloved of God, etc.; by c. 1300 it could mean "betrothed lover," and by late 14c. it had the pejorative sense "concubine, mistress, gallant." For loss of medial -f-, compare had.
Proto-Indo-European root meaning "to care, desire, love."
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit lubhyati "desires," lobhaya- "to make crazy;" Persian ahiftan "to be tangled, be hit down, be in love;" Latin lubet, later libet "pleases," libido, lubido "desire, longing; sensual passion, lust;" Old Church Slavonic l'ubu "dear, beloved," ljubiti, Russian ljubit' "to love;" Lithuanian liaupsė "song of praise;" Old English lufu "feeling of love; romantic sexual attraction," German Liebe "love," Gothic liufs "dear, beloved."
Old English lufu "feeling of love; romantic sexual attraction; affection; friendliness; the love of God; Love as an abstraction or personification," from Proto-Germanic *lubo (source also of Old High German liubi "joy," German Liebe "love;" Old Norse, Old Frisian, Dutch lof; German Lob "praise;" Old Saxon liof, Old Frisian liaf, Dutch lief, Old High German liob, German lieb, Gothic liufs "dear, beloved"). The Germanic words are from PIE root *leubh- "to care, desire, love."
The weakened sense "liking, fondness" was in Old English. Meaning "a beloved person" is from early 13c. The sense "no score" (in tennis, etc.) is 1742, from the notion of playing for love (1670s), that is, for no stakes. Phrase for love or money "for anything" is attested from 1580s. The phrase no love lost (between two people) is ambiguous and was used 17c. in reference to two who love each other well (c. 1640) as well as two who have no liking for each other (1620s, the usual modern sense).
To fall in love is attested from early 15c.; to be in love with (someone) is from c. 1500. To make love is from 1570s in the sense "pay amorous attention to;" as a euphemism for "have sex," it is attested from c. 1950. Love affair "a particular experience of love" is from 1590s. Love life "one's collective amorous activities" is from 1919, originally a term in psychological jargon. Love beads is from 1968. Love bug, imaginary insect, is from 1883. Love-handles "the fat on one's sides" is by 1967.
"Even now," she thought, "almost no one remembers Esteban and Pepita but myself. Camilla alone remembers her Uncle Pio and her son; this woman, her mother. But soon we shall die and all memory of those five will have left the earth, and we ourselves shall be loved for a while and forgotten. But the love will have been enough; all those impulses of love return the love that made them. Even memory is not necessary for love. There is a land of the living and a land of the dead and the bridge is love, the only survival, the only meaning." [Thornton Wilder, "Bridge of San Luis Rey," 1927]