vt.

1. 证实，证明[（+to）]
   attest the truth of somebody's words

   证明某人的话属实

2. 作为……的证明；表明[+（that）]
   His achievements attest his devotion to science.

   他的成就是他对科学的献身精神的明证。

3. 使宣誓

vi.

1. 证实，证明[（+to）]
   Her success attests to her ability.

   她的成功表明她有能力。

v.

1. provide or serve as clear evidence of.
2. declare that something exists or is the case.