convincing

他迟到的借口不太有说服力。

His excuse for being late wasn't very ___convincing.

我觉得这部电影的结局不太有说服力。

I didn't find the ending of the film very ___convincing.

她提出了一个令人信服的增加预算的理由。

She presented a ___convincing argument for increasing the budget.