What is the difference between 诚意 and 诚信? Both words generally mean sincerity or honesty, however their usage seems to be different, sometimes, but not always.

According to my understanding, you can say, for example:


  他对我有诚意。 


but can't say:


  他对我有诚信。


However, you can say:


  他有诚信。


Can anyone please explain the difference? Can someone please translate the above sentences accurately, and perhaps provide a few other useful examples? Thanks.
诚信: means honesty and credibility

诚意: means honesty only

You can't say:


  他对我有诚信。


Because if somebody 有诚信, he/she will be always 有诚信, not only for you, but for everyone. So you just say 他有诚信 or 他没诚信.

You can say


  他对我有诚意。


意 means mood here. One can be 有诚意 now, but wasn't other times, can be 有诚意 for you, but not for others.

诚信 is a trait, 诚意 is a mood.

You can say


  他今天有诚意.


not


  他今天有诚信