Ok, So you are just warning her as to what to expect? I agree she would have to expect repercussions.
But I’m kind of confused, because it seems like you are excusing that you say you would be icy and evil to someone who would try to break up your relationship. ? That’s not a good thing. (If someone evil tried, I should have enough trust in God that He would cause Satan’s attempts to fail and thus still love God by loving the sinner.) So I am confused as to why you excuse it just because of what you would do, which is not a good thing and not what God wants us to do, difficult as that may be. I understand though you are just giving a good warning about real human emotions/behavior.
I’m not even sure the OP is trying to actually break up the relationship, although it would probably be taken as such. Warning someone is more like the scenario. (AND its entirely true we don’t know the entire story) There is a difference between trying to break up a relationship and just giving a warning to someone who may not suspect some lurking danger. He will ultimately make up his mind what he wants to do.
She can just warn him once, and that would be sufficient, however it probably is not going to go well for her. It is typical human behavior for people to want people to butt out though. No one likes meddling- like how Jesus told some people of their sins… they hated him for it, but it needed to be done for their sake. Sometimes it may not be prudent though.
Code:
OP, does anyone else that you know see your sister the same way as you do? Anyone who has seen first hand what you say she is capable of? If so, it may do you so good to try and discuss it with them a bit and share the same concerns you shared here.
If it were me, I would pray and ask the Holy Spirit for guidance on this matter. I would pray a long time on it, giving long and sufficient meditation and thought** with the Lord **in prayer. **The Holy Spirit knows how to make good come about and sometimes will move mountains so that an issue can be procured. ** Rely on God, but do make sure you pray. I would have to warn you that if you don’t want to pray then it may be that its less about concern for this young man’s good and more about personal anger or hurt towards your sister. It
is work to pray and believe.