When I was in college, a young man walking around campus approached me and told me that he was selling magazine subscriptions as a way to help him pay for his tuition.

And, since I felt bad for the guy, I sat down with him and agreed to purchase two subscriptions. I knew something seemed suspicious when he said I had to pay for it in full in cash right then. But I ignored the red flags and gave this man all of the money in my wallet -- including my lunch money for the day.

Surprise, surprise, it was a scam and I never received my subscription.

The older we get, it seems, the less likely we are to trust others. I trust others way less than I did back then. But while I have gotten better at deciphering scams, I still have trouble determining who to trust in everyday life.

I have started to expect people to let me down. I'll meet someone and think, "It's just a matter of time before this person screws me over." But I will try to push it out of my head and think, "I need to stop expecting the worse." But this makes it hurt even worse when I finally let my guard down, finally trust someone, and I get screwed over and used just the same.

I'm sure I'm not the only one to experience this. Somedays it's tempting to just become a hermit — take refuge inside my apartment where no one can hurt me. But I know this is unrealistic and would be a very lonely existence.

So what should you do? How do you walk that thin line between protecting yourself from getting hurt and becoming a paranoid person who thinks everyone is out to get you? How do you distinguish genuine people from those feeding you a line of crap?

Here's some tips on how to learn if you can trust someone who has recently entered your life:

• Don't disclose personal information about yourself when you first meet someone, Dr. Phil says, and instead listen to the other person. Why should you tell them something about you if they're not willing to do the same? This is something I struggle with because I usually say whatever I'm thinking. But, as Dr. Phil says on oprah.com, "When you tell people what you're thinking or doing, you are making a decision to empower them with information, and you may be unintentionally giving them ammunition they can use to exploit you, compete with you or somehow get in your way." Don't feel like you need to fill a void in conversation; sometimes it's best just to be quiet.

• Determine if the person has something to gain by acting against your interest, Marty Nemko Ph.D. wrote in Psychology Today.

 • Does this person's words match their actions? According to expressivecounseling.com, "When trustworthy people say something will happen, it usually does."

• Look for the traditional signs to tell if someone is lying, which, according to healthguidance.org, are: They avoid eye contact or stare at you more than normal in an attempt to compensate; they will make certain gestures like swallowing repeatedly, blinking rapidly or scratching themselves; they will touch their nose, mouth or ear with their hands; their voice will be a little higher in pitch and/or they look up and to the right, which stimulates the imagination part of the brain, instead of looking up and to the left, which is used to recall memories.

• You also need to learn to trust yourself. Trust your own intuition and, if something seems wrong, don't just ignore it. If you don't feel comfortable in a situation or with what someone is asking you to do, trust your gut and say no (like I should have done when asked to subscribe to that magazine).

But remember — there are good people in the world, and, just because you've been hurt before, that doesn't mean you should shut out everyone you meet. You could miss out on meeting a lot of wonderful people if you do that. Even after taking all these steps, it doesn't guarantee that you won't get hurt. But sometimes it's worth it to just take the leap.

Shelly Bullard writes on Mind Body Green, "Walling ourselves off from each other only perpetuates the problem. This does not keep us safe; it keeps us lonely."