"Hij zei dat zijn eerlijkheid geen cent zou kosten."
Translation:He said that his honesty would not cost a cent.
Besides the obvious context, how can we tell the difference in pronounciation between:
There is no difference in pronounciation.
(Except in certain dialects in Limburg, in which 'ij' is pronounced like 'ie' and 'ei' like 'è' or 'ij'.)
Sincerity is not necessarily being honest, it has more to do with the way you act and look. You can look very sincere, so the message makes a greater impact on the listener, when you talk about important matters, though these matters do not have to be true. Honesty is only about being true, not lying about things. You can be both, but they are different.