Hi Tinanam, If you're talking about something that you've already got, for example a good job or a quality product by a good price, then you can say that it is too good to be true with the meaning that you still cannot believe that it has happened or you have got it. However, I saw this expression used more frequently in situations when a person has not have something yet and hesitate to buy or participate because this something looks a bit dubious. For instance, if you see a gold Rolex being sold on the Internet for 80$ with delivery from Switzerland then you can assume that this offer is too good to be true and reasonably refrain from buying this precious thingy.
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