He sent about 2.2 billion spam emails over a period of around one and a half years.

The sentence is grammatically correct.

She is a girl full of sentiment.

As an advocate for animal rights, I believe that all sentient beings, including non-human animals, should be treated with respect and compassion.

As the popping sound of the fireworks stopped, it suddenly became quiet around me. The smell of gunpowder somehow put me in a sentimental mood.