noun / adjective
sooth
SOOTH/suːθ/
What is true or real.
In sooth, the ring lies beneath the lifted cloth.

Etymology
Old English soð used 'true, real' as a noun: what is true, or truth itself. That meaning survives in archaic sooth and in forsooth, 'in truth.'
In context
Is it indeed sooth that you have been a captive upon this island?” “It is true, fair sir.