You should, because it would be the "proper" thing to say So yeah, I have no idea where OP's impression of such happenings come from, most of them in reality either ends in bloodshed directly or via the scandal detour @_@b
Half-brother and half-sister are genetically related. Stepbrother and stepsister are not as they are children by your stepparent through a previous marriage. (unless they married someone else within the same family... which is just all sorts of wrong)
dats stupid! i wub never do dat kind of thg! either go ahead n approach da target or not doin nth n give up.