The safer sequence is to view the property, read the actual lease, confirm the person you are dealing with is really the landlord or their authorized agent, and only then send a deposit, ideally by a traceable method rather than cash or an untraceable transfer to someone you have never met in person.
Paying before viewing, paying to reserve a unit sight unseen, or being asked to send money through an unusual or international payment method are all signs the listing may not be legitimate, and before signing anything, it is worth checking that the rent itself fits your budget using the same rough guideline lenders use, about 39 percent of gross income on housing costs.
If a deposit is requested before you can view the unit, treat that as the answer to whether you should pay it. Get your hand-reviewed valuation from Joel Dyck.