Sore wa tannaru uwasa dakara, ki ni suru hitsuyō wa arimasen.

That is a mere rumor, so there is no need to worry about it.

Kare ni eki de atta no wa, tannaru gūzen ni suginai.

Meeting him at the station was nothing but a mere coincidence.

Watashi to kare wa tsukiatte iru wake dewa naku, tannaru tomodachi desu.

He and I are not dating; we are just friends.

Konkai no chikoku wa tannaru fuchūi dewa naku, taichō furyō ga gen'in datta.

This lateness was not due to mere carelessness, but was caused by poor health.

Sumātofon wa tannaru dōgu de ari, dō tsukau ka wa ningen shidai da.

Smartphones are mere tools, and how they are used depends on the human.

Futari no aida no toraburu wa, tannaru gokai kara shōjita mono da.

The trouble between the two of them arose from a mere misunderstanding.