My girlfriend and her best friends ! Please advice !!?

[Goncalo]

So i started dating with this amazing girl. She´s my soul mate so perfect. But the problem is that she has a lot of best friends (guys). And im a little jealous. She said that loves me very much and would never cheat on me... but this is the first time im on a serious relationship so im insecure. She is considered " hot " by all the guys if you know what i mean... so guys hit on her. But yesterday the best friend published on her facebook wall " I love you <3 " and she commented " what a liar ". But i saw a comment from her on 1 pic of him that says " I love you <3 you´re beautiful ". She said she loves me very much... and promised me that would never cheat but.... im so insecure.... Please advice !!! What should i do ?!?! Thanks