My sister is dating a man I do not trust. How do I tell her I don't want her dating him?

You cannot stop her dating the person of her choice,
in this case you have to grow up laws have changed and
does not favour this kind of situation.

I won't ask you to stay out of your sister's business because I know you're concern about your sister, you want to protect her from getting hurt. I'm sure you love your sister very much. I believe you're a very good brother, she's lucky to have such a good brother. However, she's an adult already, all you can do is tell her honestly how you feel about that guy. Even give specific example why you come up with this conclusion. Let her know you'll be there for her no matter what happened. Control is never a good idea, the more you try to control her, the more you're pushing her to that guy, cos she would think she can find "freedom" through him. Good luck and all the best.

Whoa stop it right there. It doesn’t matter if you pay her bills, she lives under your own roof, and you pay also for her car. No matter what you do for her, still you have no right over her when it comes about her intimacy and private life.

I don’t know if she is actually “owning” you anything, but no matter what, you can not tell her who she is allowed to date and who she is not.

That “rule” you have made makes no sense, and could even be brought up into court against you if she would like to do so. Think I’m exaggerating? Do some research and you will see it.

Now, if you want to give her advice on her love life, then go ahead. I think it might be too late now because she probably doesn’t see you as a sister but more like a evil dictator that wants to rule her life. And is all your fault.

If I were you, I would sit down with her, apologize for the way you have treat her (imposing those stupid rules) and explain to her that you made a mistake and that you just want the best for her. Tell her how you feel about this guy, and that she should be very careful with him.

No matter what, do not forbid her from dating or going out with anybody else ever again. She is way too old now to be playing that game. If she wants to date a pervert, or a sick person, or a terrorist, is her own decision as a grown up adult. You can and should tell her how you feel and give her all the advise you can for her protection. But the final decision is hers, not anybody else, and even less yours.

I wouldn’t be surprised if she is dating that man just to get you mad. That is the classic example of what happens when someone tries to impose an unfair rule.

Hope you can regain her trust, because how I see it right now, I don’t think she is going to listen to you at all.

Well, in a situation like this, you really can only give your opinion and why. She's an adult, therefore, she's old enough to make her own decisions and with that of course, follows consequences of any kind. Just let her be and do her own thing, and I say this because, 1. you don't have much choice, and 2. if things don't work out, she'll learn from it, you know?
Good luck!!

Did you guys make the rule together? or is that just your rule...
You are going to have to let your sister make her own decisions....I know how you feel... I have 5 sisters and I have not always liked the guys that they hung out with, but ultimately it is going to be her choice... if he's not right for her in time it will prove its self....now if you know something about him that you think is going to cause her to not be safe then by all means say something...

When i was in a relationship with the wrong person at 19...my mom used to be so worried along with my sisters...and i would not listen to anyone..even though i respect them...
My sister had warned me and appreciated the fact that i was dating a guy they did not quite like. But what made me realise that he trully wasn't worth it..wasnt until i found out for myself...and i never had to blame my sister or mom for not liking him or being the reason i broke up with him...
so let her learn by herself...she will come to know soon...besides she is old enough to discern between good and bad...

Your sister is old enough to make up her own mind at this point. She is an adult and you have to respect her as one. Be close to her so that you can be there in a shot if you are needed. Some people are just really bad at first impressions and you may have caught him on a bad day. Give it a little while and try another meeting you may end up liking him.

Ummm to be perfectly blunt "In the past, I have generally made a rule that she is forbidden from dating people I don't like," is in no way ok. I can see from that alone that you have had issues with past boyfriends. Are you sure you just don't want a male figure taking away from your relationship with her?

I understand the protective reaction and understand you want her to remove the worry, but you are 27 and she is 24. You don't control her decisions or life.

tell her how you feel, but there's no guarantee that she will listen. if she doesn't respect her choice, but don't hang around her when she is around. i had a similar situation with my bf. he started hanging around a new guy from work. I met the guy twice and there was just something about him that wasn't right. so i told him how I felt and that I didn't want to hang out with him when this other friend was around. so he said ok... not even a week later the guy was fired for stealing a gas card and using it. kind of funny to, my bf had a gas can with some gas in it at his house and miraculously the gas disappeared around the same time! needless to say I was right. So just tell your sis and hopefully she will figure it out before anything bad happens.

UNFORTUNATELY theres really nothing you can do. She is an adult and she is going to date who she wants and she will get hurt and make mistakes. its all a part of life. You can tell her how u feel and let her know that u r there for her. BUT if you protest too much it may attract her to him more! Just tell her politely that u dont care for him- that u cant put your finger on it but something just rubs u the wrong way. Let her know she can call u 24 hrs a day and u r there for her whenever she needs you! Thats what big brothers are for! I know u want to protect her but noone can protect her from life.

It won't matter. I'm telling you from experience. My sister dated a guy who was not trust-worthy and ended up cheating on her. I told her that I didn't trust him. You know how you just get that feeling about people. Well unfortunately I was right. So, you may not be able to prevent her from falling, just make sure you're there to help her up if she does. Being a good sister isn't always about being able to prevent, it's about supporting her when she needs it most. :)