1. In the past, she was scared of her own shadow, but over time, she gained confidence and became more assertive.
2. As a leader, it's important to be confident and assertive, because make yourself all honey and the flies will devour you.
3. Even though he's usually quiet and unassuming, my brother can be incredibly assertive and commanding when he's at home - every dog is a lion at home, as they say.
4. When dealing with customer service, it can be helpful to be assertive and persistent, as the squeaky wheel gets the grease and is more likely to receive a satisfactory resolution.