I saw my best friend's boyfriend kissing other girl, he has a lover!
If I tell my best friend, she will get mad and sad, and I don't want it.
but If I don't tell to her, she will think I'm a liar and nevermore will trust me.

what should I do now?

i'm coming here later to see the results...

tell her it's better to get it over with. if she hears from someone else, she'll ask you if you knew, and would get mad that you didn't tell her in the first place. telling her now would be saving her from wasting her feelings

obviously tell her. is it better to know and get over it as soon as possible or never knowing until a few weeks after, realizing how blind you were?

I think it's better if you tell her. She'll be heart broken sooner or later. I don't think she'll be mad...well, mad at her bf ..but you should tell her. She shouldnt be spending time with a boy thats cheating on her right? So you should tell her.

you should probably tell her. even though she might have a hard time believing it at first. good luck though.

tell her. she'll be grateful to you that you did later.

I would tell her. Having a good friend hurts, but it's probably best for her. Don't say anything drastic tho. Just tell her what you saw and leave it at that.

thanks gang, im going to tell her! its better...she can lost the stupid bf, but I want she to know she always will have a friend: ME

so, people, TYSM!!!! I'm going to tell her!

if you don't tell her, then you're more of a bad friend than if you tell her. even though it will hurt her feelings, it's the best thing. she'll end up finding out eventually and will be even more heartbroken.

tell her. he is scum and should be kicked where the sun dont shine.
if you dont tell her, he'll either keep f**kin around on her, or she'll find out herself and it might be worse than if you sat her down alone and gently broke it to her. i know you dont want to make her sad&mad, but its better she not be with that type of male whore.

Just tell her. she doesnt deserve to be cheated on continuously so just tell her straight out so the sooner she will be in finding a better man.

-Moved to Relationships-

Tell her. Your best friend will be more emotionally hurt and heartbroken if her boyfriend and his lover's relationship progressed or found out later.

If she is your best friend, then you should do something for her good sake.

Eventually she'll get dumped because guys usually dump the original gril they were going out with. Just tell her and then let her have fun dumping him and being mad. I would.

that's good that you're gonna tell her, she deserves to know what's going on.