Is it risky to use the same broker representing both me and the buyer?

Yes, there's a real conflict-of-interest risk, because a broker representing both sides can't fully advocate for the best possible price and terms for you while simultaneously doing the same for the buyer — those goals often point in opposite directions. A broker in that position is generally expected to disclose the dual role and act even-handedly rather than favouring either side, but "even-handed" is a much weaker position for you than a broker working exclusively in your interest.

Where the sale includes real property, Ontario's real estate brokerage rules generally require a broker to obtain informed written consent from both parties before acting for both sides of a single deal — a formal recognition that this arrangement needs to be knowingly agreed to, not assumed. Outside a real-property component, that specific regime may not apply, but the underlying conflict-of-interest concern is the same as a matter of general agency principles. If you're offered a deal where the same broker represents the buyer, ask for the arrangement in writing, understand exactly what it changes about whose interests are being represented, and consider having a Treadstone business lawyer review the terms before proceeding.