Definitions of truly:

• adverb:   in accordance with truth or fact or reality

  Example: "She was now truly American"

• adverb:   by right
• adverb:   in fact (used as intensifiers or sentence modifiers)

  Example: "A truly awful book"

• adverb:   with sincerity; without pretense

  Example: "We are truly sorry for the inconvenience"

• name:  A surname (very rare: popularity rank in the U.S.: #41804)