Both fürchten and befürchten mean "to be afraid" in some sense, and although it's a bit confusing at first, have no fear! Let's first take a look at some of the differences, starting with fürchten:
Es war richtig gewesen, den Wolf zu fürchten,
It had been right to fear the Wolf,
und richtig sich deshalb ein Steinhaus zu bauen.
and therefore right to build a stone house.
Captions 80-81, Märchen - Sagenhaft - Die drei kleinen SchweinchenPlay Caption
Denn ihn fürchten sie: den Adler.
For it is the one they fear: the eagle.Play Caption
The verb fürchten is usually translated as "to fear" and can be used to describe the state of having real fear, of being truly afraid of something like a dangerous animal. But it can also be used to show fear of a situation:
Viele Demonstranten fürchten,
Many demonstrators fear
dass Minderheiten in den USA nun kein Gehör mehr finden.
that minorities in the USA will now no longer be heard.
Captions 41-42, Tagesschau - Amtseinführung von Donald TrumpPlay Caption
The verb fürchten is also often used reflexively:
Ich trag' mein Licht und fürcht' mich nicht...
I'm carrying my light and have no fear...
Caption 3, Sankt Martin - Das LaternenliedPlay Caption
Therefore, ich fürchte mich is another way of saying ich habe Angst or "I am afraid," and afraid in a serious way.
The verb befürchten, on the other hand, is never used reflexively and is generally used in situations where you're not literally afraid or having serious fears, but rather in situations where you are merely worried about something.
Sie befürchtete, dass ihr Herr noch immer in Gefahr war.
She was afraid that her lord was still in danger.
Caption 71, Märchen - Sagenhaft - Ali Baba und die 40 RäuberPlay Caption
This could also have been translated that "she was worried" about her lord.
Es ist, wie ich befürchtet hatte.
It is as I had feared.Play Caption
So even though befürchten is translated here as "to fear," it could equally have been translated as "to expect" with the implied connotation of expecting a negative development.
Unfortunately, sometimes even native German speakers use fürchten (to fear) as a way of exaggerating a circumstance where befürchten (to be worried about) would be more appropriate, and also vice versa. The German Duden dictionary, the standard for the German language, is quite clear on its definitions of the two words, however. To reiterate: fürchten should generally be used to express real, direct fears, and befürchten in milder situations to express worry.
Translate these Duden definitions of fürchten and befürchten, then go to Yabla German and find some more examples of videos using these verbs.
1. vor jemandem, etwas Angst haben; Unangenehmes ahnen, befürchten
2. Furcht empfinden, Angst haben
3. sich vor der Prüfung fürchten
4. vor jemandem Ehrfurcht haben
befürchten (only one definition):
(etwas Unangenehmes, was vielleicht eintrete könnte) aufgrund bestimmter Anzeichen oder intuitiv erwarten, kommen sehen.
The Swiss have it easy: they completely eliminated the ß (eszett or "sharp s") some years ago, but since we are teaching Standard German at Yabla, we should learn a few general rules about which words use s, ss, and ß.
1. Single s
There are no words in German that begin with ss or ß, so that rule is easy. A single s will usually come after the letters l, m, n and r when a vowel follows the s, with words such as: der Balsam (the balm), die Bremse (the brake), and sparsam (economical):
Das ist sehr sparsam!
This is very economical!
Caption 38, Der Trabi - Das Kultauto aus dem OstenPlay Caption
A single s will usually come before the letter p, with words such as raspeln (to grate), lispeln (to lisp), and die Knospe (the bud):
Knospen, Blätter oder, Früchte von Platanen zum Beispiel...
Buds, leaves or, fruit from the plane trees, for example...
Caption 26, Freilebende Papageien - Überwintern in WiesbadenPlay Caption
In most cases, only a single s will come before the letter t, with words such as die Liste (the list), pusten (slang: to blow), and prusten (to puff):
Dann will ich husten und will prusten und euer Haus zusammenpusten!
Then I'll huff and I'll puff and I'll blow your house down!Play Caption
2. Double s
The double s is usually written only after a short vowel, with words such as das Schloss (the castle), ein bisschen (a little bit), and passend (fitting):
Eigentlich hätte es gar keine passendere Rolle für sie geben können.
Actually, there couldn't at all have been a more fitting role for her.
Caption 16, Christina Aguilera und Cher - in DeutschlandPlay Caption
3. Eszett: ß
The ß is usually used after a long vowel or double-vowel combination (dipthong), in words such as die Straße (the street), der Meißel (the chisel), and stoßen (to bump, to repel):
Gut, und die stoßen sich ab.
Good and they repel one another.Play Caption
4. Verbs that vary between ss and ß
Just to make it more complicated, there are some verbs that are written with ß in the infinitive, but switch to ss when conjugated — and vice versa too! For instance the verb vergessen (to forget) uses the letter ss in the infinitive and present tenses (ich vergesse, I forget), but switches to the ß in the past (preterite) tense:
Belle gewann das Biest so lieb, dass sie seine äußere Erscheinung darüber völlig vergaß.
Belle became so fond of the Beast that she fully forgot about his outward appearance.
Captions 61-62, Märchen - Sagenhaft - Die Schöne und das BiestPlay Caption
Do a search on Yabla German and see if you can find some more examples of verbs that vary between ß and ss in their infinitives and their conjugations.