VERB
说明，表示，证明（某事属实）
To attest something or attest to something means to say, show, or prove that it is true.
例句
Police records attest to his long history of violence...
警方记录证明他有长期从事暴力活动的前科。
I can personally attest that the cold and flu season is here...
感冒和流感季节来了，对此我有切身体会。