plausible

plau|sible /pl'ɔːzɪb^əl/
1 [ADJ]
An explanation or statement that is plausible seems likely to be true or valid.
A more plausible explanation would seem to be that people are fed up with the Conservative government...
= reasonable
● plausibly [ADV] ADV with v
Having bluffed his way in without paying, he could not plausibly demand his money back.
● plausibility [N-UNCOUNT]
...the plausibility of the theory.
= credibility
2 [ADJ]
If you say that someone is plausible, you mean that they seem to be telling the truth and to be sincere and honest.
He was so plausible that he conned everybody.
= believable