Learn French: Son image était devenue désastreuse à cause de ces rumeurs. - His image had become disastrous because of these rumors.

Son image était devenue désastreuse à cause de ces rumeurs.

His image had become disastrous because of these rumors.

Breakdown of Son image était devenue désastreuse à cause de ces rumeurs.

his/her/its (son, sa, ses)

devenir

to become

Questions & Answers about Son image était devenue désastreuse à cause de ces rumeurs.

Why do we use à cause de instead of parce que or grâce à here?

Parce que means "because" and must be followed by a full subject and verb. Here, we only have a noun phrase (ces rumeurs), so we need the preposition "because of". We use à cause de instead of grâce à because the outcome (having a disastrous image) is negative. Grâce à is only used for positive outcomes ("thanks to").

Why is the verb était devenue and why does devenue have an extra "e" at the end?

This is the plus-que-parfait (pluperfect) tense, meaning "had become". Devenir (to become) is a verb that uses être as its helper verb in compound tenses. Because it uses être, the past participle must agree with the subject. The subject is the feminine noun image, so devenu gets an extra "e" to become devenue.

Since image is a feminine word, why does it use son instead of sa?

You are right that image is feminine, but it starts with a vowel. If we used sa, it would be sa image, which creates an awkward clash of vowels. To make pronunciation flow smoothly, French uses the masculine son before any feminine singular word that starts with a vowel or a silent h.

Could son image also mean "her image"?