There are a number of signs that can show you when someone is jealous of you. You can look at their facial expressions or body language when they talk to you. These people are insecure and downright petty. They will do hurtful things to make you feel bad about yourself.
They are competitive on a personal level, point out or exaggerate flaws,make up lies,gossip about the person with others. These are a few signs. Don't concern yourself, they feel inferior and really can't help it.