There's no reason to trust anyone, unless you've gotten to know them well and have found them to be trust-worthy. If you wait until you trust someone to go on a date, you'll never go on a date. The purpose of spending time with potential partners is to find out if they are trustworthy. Dating is like shopping. You don't purchase everything you sample.
It's perfectly fine to look at someone you don't know well as someone who might break your heart. That's reality. On the other hand, you know you're not the only good person in the world. Other good people are out there. So it makes sense to give others a chance to show you who they are. Then base your expectations of others on what you learn about them.
The love you want does exist. To find it, you have to take some risks. No one will come into your life guaranteeing that they'll never hurt you. But getting hurt now and then is not fatal. It's part of life. It's a price we have to pay to participate in life. The way to reduce getting hurt is to not have big expectations of someone you don't really know. You only know someone after you have spent a lot of time observing them with an open mind. People give off a lot of clues as to what they are about.
When someone acts like a creep, they might be doing you a favor. They are showing you who they are. This alerts you to not waste your time on this person.