Best friends

So I learned that I can trust my best friend barely, and I learned she don't like my advice...
My best friend is a person who won't take their own best friends advice for nothing...She likes this guy that I went out with last year and she ended up telling me that she likes him some time last week. Well I kept telling her don't go out with him because if you go out with him he will....
*Cheat on you with girls he meets on X-Box
*Won't talk to you after the first month going out
*And if ya break up he will end up calling you names afterwards like....(Ex. Skank, or even B*tch)
I mean she asked me for what she should do and she went behind my back and started to go out with him after I gave her advice and what worse is that its only been 6 months since me n him broke up me and her made a deal in 4th grade that if one of us want to go out with one of each others ex's(I would never date any of her's their all ugly , she mainly goes after my ex's) and so we told each other we would wait 10 months before we star going out with one of each others ex's

So a best friend basically will only take the stupid advice from some one else and not the smart advice form their best friend...I have a new best friend now and her name is Kendall....