When we use "I need" at the start of a sentence it sounds like pleading rather than empowered. It makes us sound needy.

Swap "I need" with "Please" to sound polite and confident.

"I want" sounds emotional and lacking in confidence. 

It is better to use a conviction instead of a 'want', and replacing it with "I'm convinced" or "I believe".

Guessing conveys a lack of surety. We use it to avoid lying or exaggerating, but it conveys our lack of knowledge.
Reframe that with '" expect" or "should" to convey confidence.

"I hope" carries a big 'If', and it feels the speaker has no control over the outcome, conveying uncertainty, and can feel like the speaker is untrusting of the other person.

Replace "I hope" with "I look forward to" or a similar more confident-sounding phrase.

Using 'I suppose so' indicates detachment and lack of interest. Use a more enthusiastic response like "Definitely".

Language is a powerful force and the words we use travel fast and can affect our reputation and influence. Using the right words can make our power and confidence soar high.