The swear filter doesn't take space into account so you will have to read your sentence twice or even thrice to notice any bad/swear words coming with it unnoticed.
For example: I have run out of pokeballs, I am going to replenish it. This might look like a normal sentence but as swear filter doesn't count space, you will be warned for this as it contains shit in it. "...replenish it".
Thanks