This is the 11648th most frequent Turkish word.
fikirlerinin
"Fikirlerinin" means "of his/her/their ideas" or "of his/her/their thoughts" in English.
In this sentence, 'fikirlerinin' is the possessive form of 'fikirler' (ideas) referring to the ones belonging to 'you' and is marked in a genitive case context.
Fikirlerinin benim için çok değerli olduğunu bilmelisin.
You should know that your ideas are very valuable to me.
Here, 'fikirlerinin' again indicates possession, referring to 'your ideas,' connected to a statement about their potential usage/relevance.
Fikirlerinin farklı alanlarda kullanılabileceğini düşünüyorum.
I think your ideas can be used in different fields.
In this example, 'fikirlerinin' pertains to 'your ideas' as the subject needing development, aligning with the goal of the statement.