Sentence examples similar to certainly not sure why from inspiring English sources

As a society we tend to be skeptical whenever a couple's ages are so far apart but I'm not sure why; there are certainly enough relationships in which the couples are about the same age that don't last, either.

I'm not sure why I'm so shaken – Morgan Freeman certainly counts as a stranger.

I'm not sure why I remember that exactly, but it's certainly an appropriate sentiment about being a teenager.

I'm not sure why people want to believe this for it's most certainly untrue.

We're not sure why this is called the Mullet Ring, but it's certainly a "gentleman's secret".

Not sure why yet.

He is not sure why.

He was not sure why.

Researchers are not sure why.

She is not sure why.

Very weird, not sure why".