| swear up and down(verb, expression, idiom, phrasal verb, assert) |
| take an oath(verb, expression, idiom, assert, undertake) |
| testify(verb, assert, undertake, affirm, promise) |
| trust(verb, assert, undertake, affirm, promise) |
| vouch(verb, assert, undertake, affirm, promise) |
| vow(verb, assert, undertake, affirm, promise) |
| warrant(verb, assert, undertake, affirm, promise) |
| affiance(verb, promise, swear, covenant) |
| affiancing(verb, promise, swear, covenant) |
| asservate(verb, promise, swear, covenant) |
| bear witness(verb, expression, declare, testify) |
| cross heart(verb, expression, trust, promise, swear) |
| declare(verb, testify) |
| give word(verb, expression, assert, promise, swear) |
| give word of honor(verb, expression, idiom, promise, swear) |
| live up to(verb, expression, idiom, promise, swear) |
| pledge(verb, undertake, promise, swear, vow) |
| sign for(verb, expression, promise, swear, covenant) |
| swear on bible(verb, expression, idiom, promise, swear) |
| undertake solemnly(verb, expression, promise, swear, covenant) |