This is what the Lord Almighty says:

“Do not listen to what the prophets are prophesying to you;
    they fill you with false hopes.
They speak visions from their own minds,
    not from the mouth of the Lord.” Jeremiah 23:16

            False hope gives comfort for a short period of time.  To someone in utter distress, a “guess” or a “hope” or a “wish” may distract them from the real truth of the matter.

            For example by saying, “Everything’s going to turn out okay” feels good at the moment but who really knows.  Trusting God and leaning on Him for strength is always true and can never be wrong.

            By saying to a grieving person, “Your loved one is with God” when you don’t really know their salvation story, could be true or it could not be true but should you bring up such a matter during intense grief?  No, give hope, but don’t say things that you don’t really know for sure.

            What’s always hopeful?  “God is in control,” “God cares for you,” “God is sending help right now,” “The Holy Spirit grieves with you,” “Trust God, stay strong and don’t be afraid.”

            We don’t want to say things that later don’t turn out to be true.  People can lose their faith in God who didn’t pull through like you said He would.