I solemnly declare submitted papers to research and summarize the results as true.

本人郑重声明所呈交的论文是研究工作和取得成果的总结，内容真实。

youdao

"I solemnly declare that the tiger picture was real, and was not faked," Zhou wrote.

周写道：“我郑重宣称虎照是真的，不是伪造的。”

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I solemnly declare that the above information is true and correct, and understand that this declaration has the same force and effect as if given under oath.

本人郑重声明以上资料真实无误及明白此声明具有与宣誓下作供之同等效力。

youdao

"I, Julia Eileen Gillard, do solemnly and sincerely affirm and declare that I will loyally serve the Commonwealth of Australia in the office of prime minister, " she said in the ceremony in the Australian capital, Canberra.

BBC: Gillard sworn in as Australian prime minister