Yes, decent people do exist. Love and happiness does exist.
It's a fine line when you give your heart to someone. You're expected to be absolutely trusting and vulnerable. When you let your guard down and end up being betrayed, that's the worst feeling. I truly believe that if you are open to it, love will find you. Maybe not immediately, but eventually you'll find a decent person who will show you that trust, love and happiness does exist.
I'm sorry he lied to you. Let yourself feel the pain, grieve it, then try to move on. It may take some time, but if you do things each day for yourself to try to be positive, it'll be easier going. I let bad experiences influence me to the point where I gave up hope for too many years and I couldn't move on. Life is too short, the most important thing is love. I think there is true honest love out there for everyone - some already have it, others are seeking, and lots are afraid to let themselves be vulnerable enough to allow it. Just don't give up hope.