Justly vs Forthrightly - What's the difference?

As adverbs the difference between justly and forthrightly

is that justly is in a just or fair manner; rightfully while forthrightly is in a forthright manner.

(-)

In a just or fair manner; rightfully.

* 1890 , Robert Franklin Pennell, History of Rome :

His valor, wisdom, and justice made him justly popular, but caused him to be regarded with suspicion at Rome.

With a just or fair use of language; with good reason, properly.

* 2012 , Jay Newton-Small, ‘Gangless in Glasgow’, Time , 1 Oct 2011:

But the city on the River Clyde can justly claim to have turned the tide.

(obsolete) With great precision; accurately, exactly.

*, II.14:

It is a pleasant imagination to conceive a spirit iustly ballanced betweene two equall desires.