担保

I vouch for the accuracy of my information.

I can answer for her honesty.

I'd stake my life on it. / I bet my life on it.

give one's word of honour; pledge/pawn one's honour

vouch for him

give security for repayment

She gave him her title deed for the house in surety of the loan.

lifetime guarantee

material security

double securities

personal security

necessary security

furnish/offer security

decline security

accept security

obtain security