Can we ever really know each other in a relationship? Some great thinkers have thought not. The "other" forever remains a mystery to us.
They could have been talking about online dating. In yet another example of how what connects us can be used against us, we're seeing more and more "romance scams" these days, where people open up their hearts and unfortunately end up opening their wallets as well. Entire life savings can be lost.
Sometimes these are called "dating", "sweetheart" or "love" scams. Under the guise of romance, trust is built up, and this leaves people vulnerable to fraudsters.
Long-distance affairs
I know a handful of happy couples who initially met online, so it obviously works for some. The shady stuff seems to emerge over long distances, in particular, when a love interest seems to need rescuing.
"It's a pity I found myself in this problem, I don't like asking for favours, this is the first time I am in this condition. I will be happier if this problem can be solved and I will happily be with you."