Troth

Troth (?), n. [A variant of truth. See Truth.] 1. Belief; faith; fidelity.

Bid her alight
And hertroth plight.
Shak.

2. Truth; verity; veracity; as, by my troth. Shak.

In troth, thou art able to instruct gray hairs.
Addison.

3. Betrothal.