Speaker's feelings towards his choice:
The speaker in the poem "The Road Not Taken" by Robert Frost does not necessarily feel that he made the wrong choice in taking the road "less travelled by." He mentions that both roads were equally fair, and he chose the one less traveled by, which made all the difference. This implies that he is content with his decision and believes that taking the less popular path has had a significant impact on his life.

Reason for the sigh:
The speaker sighs at the end of the poem not out of regret, but out of reflection. The sigh can be interpreted as a moment of contemplation or acknowledgement of the choice he made. It is a sigh of satisfaction and realization of the significance of his decision to take the road less traveled by. The speaker understands that his choice has shaped his life in a unique way, leading to experiences and opportunities that he may not have had if he had taken the more common path.

Regret:
The speaker does not express regret in the poem. Instead, he acknowledges the impact of his decision and the difference it has made in his life. By choosing the road less traveled by, the speaker has embraced individuality and independence, which has set him apart from others. The sigh at the end can be seen as a moment of reflection on the journey he has taken and a recognition of the value of making unconventional choices.
In conclusion, the speaker in "The Road Not Taken" does not regret taking the road less traveled by. He sighs not out of regret, but out of reflection and realization of the significance of his choice. The poem serves as a reminder of the importance of making independent decisions and embracing the path less traveled.