Fiancer
Defined in 3 dictionaries — Ballentine's (1916), Bouvier (1914), Black's (1910)
Ballentine's Law Dictionary
James A. Ballentine · 1916
To promise.
Bouvier's Law Dictionary and Concise Encyclopedia
John Bouvier; revised by Francis Rawle · 1914
To pledge one’s faith. Kelham. FIANZA (Span.) Surety. The contract by which one person engages to pay the debt or fulfil the obligations of another if the latter should fail to do so.
Black's Law Dictionary
Henry Campbell Black, M.A. · 1910
L. Fr. To pledge one's faith. Kelham.