、。
She's too shrewd to be fooled.
Literal
She [topic-は] shrewd person [reason-だから], deceive [nominalizer-こと][topic-は] cannot-do.
抜け目のない 'shrewd, sharp, missing nothing' — 抜け目 'oversight, gap' + ない 'without.' 騙すことはできない 'cannot deceive' — a strong assertion. The sentence structure is causal: because she's shrewd → therefore can't be fooled.