The best way to ensure that the person you meet through a personal classified ad is trustworthy is to take your time getting to know them. Ask questions about their interests, hobbies, and what they are looking for in a relationship. Do some research on them online and make sure their story checks out. It's also important to meet in public places where there are plenty of people around, so you can feel safe and secure. Trust your instincts; if something feels off or too good to be true, it probably is!