This post is only about the speed of your speech.
There's nothing that says 'I am confident in what I'm saying' than speaking slowly and delicately.
There are so many fast talkers in this world that one gets tired of them, most times it seems like the person that talks too fast is very unsure of themselves and don't give thought into their words before they say them.
People that actually speak slowly however have this 'listen to me carefully' message in every word they say. I believe when someone speaks to me slowly, they have given thought to everything they are about to say and errors shouldn't be found in what they say.
Fast talkers however seem like they are smart and calculated, but I'll have you know that when someone is speaking too fast, they are mostly lying or trying to convince you.
Think about it, when a person speaks slowly, don't you feel the urge to give them full attention, especially since you'll anticipate the next word that'll flow our of their mouth.
Now listen, when I say speak slowly, I don't mean you should talk like an old man, NO! nobody wants to listen to an old man, they are boring, (albeit wise) but the funny thing is it's not what they say that is boring, but the speed of which they say it. Don't be an old man!
Look for a way that you can speak in the speed right in between an old man and a typical fast talker.
It makes you sound confident regardless of what you say.