Breakdown of Ella tiene un gesto simpático y las mejillas rojas.
y
and
ella
she / her (after a preposition)
rojo
red
un
a, an, some
Questions & Answers about Ella tiene un gesto simpático y las mejillas rojas.
Why is gesto translated as "expression" here instead of "gesture"?
While gesto often means a physical movement made with the hands, it is also frequently used to refer to a facial expression or a person's general countenance. In this sentence, un gesto simpático means she has a friendly, pleasant look on her face.
Does simpático mean she is being "sympathetic"?
No, simpático is a common false friend. It means "friendly", "nice", or "likable". If you wanted to say she is sympathetic, you would use a word like comprensiva or empática instead.
Why does the sentence use las mejillas (the cheeks) rather than sus mejillas (her cheeks)?
In Spanish, it is standard to use definite articles (el, la, los, las) with body parts instead of possessive adjectives (mi, tu, su). Because the sentence starts with Ella tiene, it is already obvious whose cheeks are being described.
Why is the phrasing tiene las mejillas rojas preferred over sus mejillas son rojas?
Using the verb tener followed by the definite article, the body part, and the adjective is the most natural and idiomatic way to describe someone's physical features in Spanish. Although translating "her cheeks are red" directly makes sense grammatically, the structure with tener sounds much more native.