How do you tell your friend that you like his sister?

Just tell your friend you like his sister and ask if hed be uncomfortable if you asked her out. If he says hed be okay with that then you at least have the option to ask her out. If hes not okay with it then you should probably just let it be.

What do you do when you like your best friends sister?

Heres what you should do:Maybe Dont. Listen. Make Sure Youre Interested. Okay, you still want to go ahead. Make Sure Shes Interested. Spend Platonic Time Together First. Tell Your Friend. Ask Her Out. Treat Her Right. Dont Dwell on the Brother Thing.More items •24 Jul 2018

Is it worth telling your friend you like them?

If you have a crush on someone who is already coupled up, its generally better not to reveal your feelings. Its unlikely to lead anywhere and you really do risk losing them as a friend because they might feel very uncomfortable being around you knowing how you feel and yet also having a partner.