I bet he forgot about the meeting.

我打赌他已经忘记了这个会议。

youdao

I bet he let slip that I'd gone to America.

我确信他无意中说出了我已去了美国。

《柯林斯英汉双解大词典》

Jeff: I bet he liked that Joan.

杰夫：我打赌他喜欢那样，琼。

youdao

I bet he's smart. Is he smart?

VOA: standard.other

And so he gets in the backseat and he says, "I bet you can't guess who I am."

他坐在后座里，然后说:“我打赌你猜不出我是谁。”

记忆犹新的乘客 - SpeakingMax英语口语达人

Anyways,I will risk forty dollars and bet you that he can jump farther than any frog in Calaveras County."

VOA: special.2009.08.29

"Mr. Sarkozy has bet he could replay the 2007 election, " said Emiliano Grossman of Sciences Po University in Paris.

WSJ: Sarkozy Fights for Survival

So it's a fair bet he won't be waving an England flag as Roy Hodgson's men begin their European Championship campaign.

BBC: Ed Miliband says you can be both Welsh and British

We didn't ask him, but I bet he has a composting toilet.

BBC: Newsnight's clock ident