Why not use several possible responses:
Code:
NPC_SCRIPT 1{
trigger_text:Hail:{
say:I am a soulbinder. I can bind you here. Do you want your [soul bound]?
}
trigger_text:soul bounded:{
FACE_TARGET
SAY:I shall bind your soul, great traveler.
CAST_SPELL 35
}
trigger_text:yes:{
FACE_TARGET
SAY:I shall bind your soul, great traveler.
CAST_SPELL 35
}
trigger_text:get me stuck me here forever and ever:{
FACE_TARGET
SAY:I shall bind your soul, great traveler.
CAST_SPELL 35
}

ok that last one was just for the fun of it