How do I turn off sent iMessage sound on Macbook

It is so disappointing that people are asking this question since 2012 but Apple does nothing!! The same on the iPhone, do we need to jailbreak our phones to delete the sound file?! pathetic

And I know what you're gonna say, restart in Safe mode or disable "Play Sound effects" in settings... yeah I can do that but I just wanna disable the outgoing message sound, NOT the incoming.

I am just listening to loud music I do not want that useless sound when the message was sent! I can see the message was sent when i press ENTER to send it.

No wonder the whole globe is brainwashed by Whatsapp