It's my word against his/hers

　　[字面意思] 我的话对他/她的话。
　　[解释] 我跟他发生争执，我俩各执一词，没有人可以证明谁对谁不对，公说公有理，婆说婆有理。你该相信谁的话，真是个难题。There were no witnesses to the accident, so it's my word against hers. 这是说不清的事情。