Faith is believing God Almighty will do just what he said he would do.
KJV
1
Now faith is the substance of things hoped for, the evidence of things not seen.

NIV

Now faith is confidence in what we hope for and assurance about what we do not see

Hebrews 11 Amplified Bible (AMP)
The Triumphs of Faith
11 Now faith is the assurance (title deed, confirmation) of things hoped for (divinely guaranteed), and the evidence of things not seen [the conviction of their reality—faith comprehends as fact what cannot be experienced by the physical senses].