firmer

This new glue makes a firmer bond.

新胶水粘得牢。

This glue is our new product and makes a firmer bond.

"这种胶水新产品,粘结力很强。"

I don’t know a lot about physics, I’m afraid. I’m on firmer ground with mathematics, which I studied at university.

恐怕对物理知道不多，但数学比较有自信，在大学学过。