You don't reason with a toddler. You can teach them, over time, to learn reason, but it certainly doesn't start that way.

My child gets spanked, but there are two important factors when doing it:

1. Never, under any circumstances, spank out of anger. There is a significant difference in disciplining a child and being angry. If my child gets spanked, it is immediately followed by a discussion of why. That way they know they fucked up, know they are loved and know that fucking up has consequences.
2. The spanking is a reset button, and you don't need to push it hard. A single swat through clothes shouldn't hurt them. If it did, that's too much, and it should never be multiple times.