There are a number of preposition words that change the meaning of a phrase when used with a particular word. For example, you can use with Fascinated different prepositions, and you will get a different meaning every time. You can see the examples below:
1. Fascinated with
Fascinated with (person)
Example: I was fascinated with Rekha.
2. Fascinated by
Example: I was fascinated by her manners and looks.