Ma'mun
No single-name Ma'mun is not cited as a proper noun in the Quran. Its root relates to words found in the Quran concerning trust and security.
Yes. The most notable historical bearer is the Abbasid caliph al‑Maʾmūn (r. 813–833), known for patronage of learning.
Yes. It is a classical Arabic name with positive connotations of trustworthiness and is acceptable across Muslim cultures.
A feminine form sometimes seen is Ma'munah or Mamunah (مأمونة), meaning 'she who is trusted.'
Common pronunciations are MAH-moon or maʾˈmuːn, with a glottal stop representing the hamza in careful pronunciation.