Running a small business involves a steady supply of conversations nobody wants to have. Telling a long-standing customer that the price is going up. Telling a supplier that the last three deliveries were late and this is the last time. Responding to a complaint that is partly fair. Raising something with an employee. These get postponed, and postponement makes almost all of them worse: the price rise becomes overdue and therefore larger, the supplier problem becomes a pattern that was tolerated, the complaint sits unanswered long enough to become a review.
The reason for the postponement is usually not cowardice but uncertainty about how it will go. The conversation is unrehearsed, the other person's responses are unknown, and the fear is of being caught without an answer - agreeing to something in the moment, or losing your temper, or backing down entirely. That uncertainty is what rehearsal removes, which is why people who have to do this professionally rehearse. The obstacle for a small business owner has always been that rehearsal needs a partner, and there is rarely one available who understands the situation and is willing to play the other side properly.
An AI tool does this well, and the way to use it is more specific than simply asking for advice. Describe the situation and ask it to play the other person - and to play them as someone reasonable but unwilling, who has their own case, rather than as someone who immediately agrees. Then have the conversation. The value is in discovering which of your points collapses when pushed, which figure you cannot actually justify, and which objection you had not anticipated. It is also in hearing yourself say the difficult sentence a few times, because the first time it is said aloud is the worst, and there is no reason for that to happen in the real conversation.
There is a boundary worth keeping. A rehearsal is preparation, not a script, and walking into a real conversation with a script tends to go badly, because the other person has not read it and will say something else. What you want to take in is the two or three points you are actually making, the figure you can defend, and the thing you are not willing to agree to. Everything else should be responsive, because the person in front of you is the reason the conversation exists. And on the substance, one check remains yours alone: whether the position you are about to defend is a fair one. A rehearsal will help you argue any case, including one you should not be making.