Can you give guarantees of their genuineness?

你能保证是真品吗？

Americans see it as a sign of genuineness and honesty.

而美国人却认为这是真诚和诚实的表示。

External criticism tests the genuineness of the source.

外部批判（审视）检验资料来源的真实性；

The expert attested to the genuineness of the document.

专家证明该文件系真品。

The genuineness of this epistle is not called in question.

真实性，这书信是不叫的问题。