vouch
v[Ipr]
1 ~ for sb/sth take responsibility for or express confidence in (a person, his behaviour, etc); guarantee 为(某人、 其行为等)担保或作证; 保证
I can vouch for him/his honesty. 我可以为他[他的诚实]作担保.
2 ~ for sth confirm (a claim, etc) by producing evidence or drawing on one's own experience(提供证据或现身说法)确定(某权利要求等)
Experts vouch for the painting's authenticity. 由专家确认该画是否为真迹.
Yes, and we must stop people walking on this floor until it's firm. It may be necessary to put up a notice saying Keep off. Another thing, we' ll have to drill a hole in the wall for the electric wires.