I assure you.

我向你保证。

youdao

You think I did it deliberately, but I assure you (that) I did not.

你认为这是我故意干的，不过我向你保证不是的。

《牛津词典》

A real pleasure, I assure you, ma'am!

真正的快乐，我向你保证，夫人！

youdao

"Among these three thousand teachers I can assure you almost 25 to 30 percent are former Khmer Rouge themselves.

VOA: standard.2010.04.19

And I said to my advisor, "No, no. I have taken chemistry in high school, and I can assure you that chemistry has no relevance whatsoever to the life sciences."

于是我就去和我导师说：,“我在高中学过化学，我向你保证化学和生命科学,没有任何关联“

麻省理工公开课 - 化学原理课程节选

Well I grew up in Michigan and I can assure you that Michiganders love all those things too and probably even more.

我在密西根州长大,所以我敢保证密西根人也很喜欢这些东西,甚至比南方人更喜欢

耶鲁公开课 - 美国内战与重建课程节选

Senator BARACK OBAMA (Democrat, Illinois, Presidential Candidate): We had an awful lot of small town mayors at the Democratic convention, I assure you.

NPR: Obama, McCain Speak At Community Service Forum

We will have developments on this in the future, I assure you.

CNN: The 100-Day Itch

Being bored is not an option for me, that I can assure you.

BBC: SPORT | Tennis | Emotional exit fantastic - Agassi