Peace be upon you and God's mercy and blessings.
Grand Ayatollah Sayyid Khamenei (may Allah protect him):
It is not permissible for a person to break their fast based on someone else's word without confirming the entry of the time. If it is a matter of taqiyya (dissimulation), then it is permissible for them to break their fast, but they must make up for it later. It is not permissible to break the fast voluntarily except after confirming the entry of the night and the end of the day either by certainty or by a legitimate reason.
Grand Ayatollah Sayyid Sistani (may Allah protect him):
It is not permissible to break the fast with non-Imami individuals, and one must rely on their certainty regarding the entry of the legal Maghrib time, and it is obligatory to make up for it if they do so, as a precaution.
Grand Ayatollah Sheikh Nasir Makarem Shirazi (may Allah protect him):
There is no objection to breaking the fast voluntarily, as his preferred view is that sunset is confirmed by the disk setting, although it is more cautious to wait until the redness in the sky disappears.
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May you be successful in all good.