this sentence: It is too good to be true, means it is very good, absolutely right, am I right?
If something is too good to be true it means that it's so unbelievably good that you are start wondering if it's really true and genuine.
If someone wants to sell you shares with gold mines, say no. It's too good to be true. You find out they are all in the Sahara desert!
If a telemarketer calls you to tell you you have won a million dollars if you just give him your Visa card number, say no. You know there is something "fishy" about it.