。
She's honest, so she'd never do something like lie.
Literal
She [topic-は] honest is [because-から] lie [object-を] told [things like-たり] does-not.
嘘をつく means 'to tell a lie' — つく (付く) here is 'to attach,' not 'to arrive.' The ~たりしない construction is a single-item version of the ~たり~たりする pattern, meaning 'doesn't do things like X' — it implies lying is just one example of things she wouldn't do. 誠実 (せいじつ) means 'sincere' or 'honest,' and から states the reason.