So far the only way I know to say "I'm sorry" is "lo siento." However, this gets repetitive rather quickly, and sometimes I'm looking for a stronger form of an apology. What other ways are there to apologize in spanish? If you are apologizing for an extremely terrible thing you've done, would you use a different phrase? How do native speakers apologize or convey regret for things they've done?
Well at least in Mexico is not common to say "lo siento" instead we say "perdón" for apologizing. The only part that I've heard "lo siento" is in movies or telenovelas.
A stronger version of "perdón" is "perdóname" or "discúlpame". You can add "por favor" at the beginning or at the end of the sentence.
Here some examples:
In Argentina, we just emphasize "Lo siento" (or "lo lamento")
Alfredo's alternatives are also ok.
'Sentir', 'perdonar', 'disculpar', and even 'dispensar' are all used depending on the reason for your apology:
You're just being polite, it is not really your fault and beyond your control.
This is the equivalent of 'excuse me'. You are responsible for the action, but it is a small or easily-justifiable matter.
You are responsible for the action, and it is a big deal.
Other words to keep in mind:
'Dispensar' is used by old people in Mexico, it is the equivalent of 'disculpar' and it is disappearing but will remain in written works.
'Con permiso' is the active and physical version of 'excuse me'. It always involves physical movement, like when leaving/entering a room or reaching in front of someone to grab something.
'Pesar' is used when something weighs heavily on you and is much deeper:
Last but not least, 'dar el pésame' is what you would say to someone who has lost someone:
Other alternative, stronger than just "lo siento":
It's also more formal than "lo siento"