no it's not like that

When presenting a sales proposition, what to respond when the receipient of the proposal says "But we don't want to be at loss"

Sentence 1: "No! it's not like that!"
State firmly. Insist that whatever "be at loss" was, or how likely that outcome might be, "NO!", insist "It's NOT like that."

Sentence 2: "You won't be at loss"
Having made the point, make the point again: It is "NOT" like that, you won't be at loss. (Here at loss can of course be many things, "loose money", "be fucked in the ass", "be defamed due to"... etc.

Sentence 3: "We will take the loss for you."
This is where you explain why he won't be at loss, because you will be. "You see, we'll be doing all the hard work, taking all the risks, bending over backwards, and then some. (go into details on the places where he might be at loss, but each case being covered by you).

Making sure to speak firmly and reasonably at each step.