There is a neat little trick to speed this up quite a bit.
*** Spoiler - click to reveal ***During your main mission on Noveria you will meet Lorik Qui'in. He'll ask you to get something out of his office. After you got what he wants you will be contacted by Gianna Parasini. She'll ask you to convince him to help her.
Now go and talk to Lorik and select the following options:
- Testify against Anoleis.
- (Charm) You'd be a hero.
After the conversation ends you'll be rewarded 25 Paragon points.
Now simply talk to him again and select these options:
- Matriarch Benezia
- Another question
- Testify against Anoleis.
- (Charm) You'd be a hero.
You'll get another 25 Paragon points. Repeat until the Trophy unlocks.
For the Charm option to be available during this conversation you will need to spend 5 points on the skill.