troth
From Longman Dictionary of Contemporary Englishtrothtroth /trəʊθ $ trɒːθ, trɑːθ, troʊθ/ noun → plight your troth2Examples from the Corpustroth• We will continue to cry at weddings because we know how bittersweet, how fragile is the troth.• Of course, if everyone knew their partners inside out, there's a good chance no-one would ever plight their troth.Origin troth (1200-1300) truth