Key signs include improved character, increased devotion to prayer, avoidance of previous sins, greater humility, and increased charity — the Prophet said Hajj Mabroor's reward is Paradise.
The scholars have identified that the primary sign of an accepted Hajj is a positive transformation in the pilgrim's character and worship after returning home. The Prophet (peace be upon him) said: 'An accepted Hajj has no reward except Paradise' (Bukhari and Muslim). While only Allah knows with certainty whether a Hajj is accepted, scholars point to several encouraging indicators.
These signs include: the pilgrim feels a greater closeness to Allah and increased love for worship, they maintain or increase their devotion to the five daily prayers, they exhibit more patience, humility, and kindness in their dealings with others, they actively avoid sins they may have been involved in before Hajj, they increase in charitable giving and good deeds, and they feel a longing to return to the holy sites. The absence of boasting about the pilgrimage is itself considered a positive sign, as sincerity is the foundation of accepted worship.
Source: Sahih al-Bukhari, Kitab al-Hajj; Sahih Muslim, Kitab al-Hajj