Emocionarse vs. entusiasmarse

In Spanish, the words 'emocionarse' and 'entusiasmarse' both relate to the concept of getting excited, but they are used differently depending on context and type of emotion.

Emocionarse

'Emocionarse' means to become emotional or thrilled. It encompasses a wide range of emotions, not only positive excitement but also feelings like being moved or touched deeply.
Me emocioné al ver a mi familia después de tanto tiempo.
(I became emotional seeing my family after such a long time.)
Se emocionó al recordar su niñez.
(She got emotional remembering her childhood.)
Los niños se emocionaron con la llegada de Papá Noel.
(The children were thrilled with Santa Claus's arrival.)

Entusiasmarse

'Entusiasmarse' specifically means to become enthusiastic or excited about something. It is generally associated with a positive and high-energy reaction.
Los estudiantes se entusiasmaron mucho con el nuevo proyecto escolar.
(The students got very enthusiastic about the new school project.)
Ella se entusiasma cada vez que habla de su trabajo.
(She gets excited every time she talks about her job.)
Nos entusiasmamos con la idea de viajar juntos.
(We got excited about the idea of traveling together.)

Summary

While 'emocionarse' can refer to a broad spectrum of emotions, including being touched and lasting sentiments, 'entusiasmarse' is more narrowly focused on becoming energetic and positively excited about something specific. Both convey strong feelings, but the nuance lies in the type and scope of emotions involved.