The word reticent is an adjective.
In Germany people were reticent; if they did talk they could be put to death.
She has always been reticent about discussing her private life. Because of nearly drowning as a child, he's reticent about attending a pool party. A mouth full of fillings makes her reticent to chew gum and eat sticky foods. After a student made laughed at him, Jeff was reticent to volunteer another answer in class.
I was reticent about revealing the source of my information. OR She was never reticent about her dislike for country music. OR He was reticent to tell the truth for fear he would be punished.
means reserved and unwilling to communicate. The man was reticent when his wife died.
A sentence with the word 'reticence': His reticence made him lonely and a less friendlier person.
Meaning : silent, quite, tighghtly closed-lips, secretive, close-mouthed I think now you can make the sentence.
Reticent
The word you are looking for is "reserved".
Reserved or reticent.
Uneffusive. Reticent. Reserved. Withdrawn. Timid
(adj.) - disinclined to speak; restrained or reserved in style