well-founded

[ wel-foun-did ]

/ ˈwɛlˈfaʊn dɪd /

having a foundation in fact; based on good reasons, information, etc.: well-founded suspicions.

Origin of well-founded

Middle English word dating back to 1325–75

Kim now knows the “well-founded fear” that asylum seekers must prove they have to be accepted by a host country.

The Canadian Faulkner |Tom LeClair |June 24, 2013 |DAILY BEAST
Assumptions that the Republican nominee automatically wins statewide office in South Carolina are well-founded but not uniform.

A GOP Star Falters |John Avlon |October 16, 2010 |DAILY BEAST
“His language is off the scale but his sense of injustice is often well-founded,” Ralph Nader told the Beast.

Jerry Brown's Worst Enemy |Benjamin Sarlin |March 2, 2010 |DAILY BEAST
There was no proof at all, nothing to link him to the crime except some well-founded suspicion.

John Grisham's Debut Short Story |John Grisham |October 26, 2009 |DAILY BEAST

In some instances, from necessity; in others, from a well-founded distrust of the public.

Abridgment of the Debates of Congress, from 1789 to 1856, Vol. I (of 16) |Thomas Hart Benton
That there were many beliefs does not destroy the fact that there was one well-founded belief.

A Miscellany of Men |G. K. Chesterton
A well-founded horror of military barbarity had the effect of separating the soldier from the civilian by an impassable gulf.

Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 6 |Various
Perhaps there was a well-founded feeling that they proved too much.

A History of the United States |Cecil Chesterton
As for Redroban, he and half a dozen of his men fled to the woods, in well-founded fear of Menendez.

The History of Cuba, vol. 1 |Willis Fletcher Johnson

well-founded

having good grounds well-founded rumours