trothful
Faithful, loyal, trustworthy.
archaic, rare
Of trothfull troth hope biddes me ſay, / That loue hath hedgde me in hir hande.
Where it comes from
From Middle English trouþeful, equivalent to troth + -ful. Piecewise doublet of truthful.
Adapted from the Wiktionary entry trothful (CC BY-SA 4.0).