2.Vous avez un devoir pour me dire des filles françaises.
...................................................................................................................
I hope I have translated the two English into French correctly.
You must tell me about French girls. [ This borders an order.]
You have an obligation to tell me about French girls. [ Maybe there is a legal obligation!]
Ok, first one: "You must tell me about French girls".
"Devoir" (must) is always followed by a verb in its infinitive form. Bravo Crack1, this is exactly what you did.
However, "dire" is "to say". What you wrote actually means "You must say me French girls". Doesn't make any sense, so let's tweak it just a little bit.
"to tell" is "parler". and "ma" should be "me".
So here's the final version: "Vous devez me parler des filles françaises".
You were very close. Keep the good work, Crack1!
Next one : "You have an obligation to tell me about French girls"
Wow, yes, it sounds like a legal obligation. Don't say that to a friend, it'd be pretty harsh.
You can translate it as:
"Vous avez l'obligation de..."
(note: "l'obligation" not "une obligation")
Don't use "un devoir". "Un devoir" also means an obligation, but it doesn't work in all contexts, and definitely not in this one (or in another way: "pour devoir").
So, here we go for the final version:
"Vous avez l'obligation de me parler des filles françaises"
or:
"Vous êtes obligés de me parler des filles françaises"
The meaning is exactly the same, but the first one is more formal than the second one.
And for the record, if you want to say "You SHOULD tell me about French girls" (and this is probably what you would use most of the time, because you are a smart guy, aren't you?), use the conditional:
"Vous devriez me parler des filles françaises".
This form, just like "should" can also be useful to give an advice:
"Vous devriez faire du sport"
"Vous devriez acheter un iPhone"
"Vous devriez manger des fruits"
"Vous ne devriez pas manger de hamburger"
I just want to throw a slight spanner in the works with "obliger" that it's worth knowing about. Fank, presumably you'd agree that when "obliger" is used 'truly as a verb' the preposition is usually "à", not "de". So for example:
Mon chef va m'obliger à travailler ce samedi.
So then, by extension, there's some tendency to use "à" in 'true passives' (i.e. with an agent introduced by par...). So for example, I think the following would be typical choices of prepositions (though contradictory opinions are welcome!):
J'étais obligé de terminer le travail avant samedi.
(obligé essentially an adjective; de used) J'ai été obligé à terminer ce travail par mon chef.
(ai été obligé a "true passive" verb form; à used)
I think the synonyms forcer and contraindre (and possibly one or two others that don't spring to mind right now) work in a similar way.
So the preposition depends on whether it is avoir or être. It is interesting grammar point.
Interessé par
Je suis interessé par les belles filles. (Hope this is correct!)
I am interested in beautiful girls.
..........................................
Mon chef va m'obliger à travailler ce samedi.
My boss will give me the green light to work on Saturday.
My boss will give his approval for me to work on Saturday. Have I translated correctly?
I wrote some more examples until I realized what a mess obligé de/à/par actually is. It's way more complex that it looks at first sight.
So here's a rule of thumb.
1) You had to do something.
Use: j'ai été obligé de
2) Someone is forcing you to do something
Use: quelqu'un m'oblige à
past:
3) Someone forced you to do something
Use: quelqu'un m'a obligé à
--
1) - (B) a été obligé de faire (W)
2) - (A) oblige (B) à faire (W)
past:
3) - (A) a obligé (B) à faire (W)
Trying to start with who was forced to do it instead of who asked for it, is tricky.
While Neil's exemple: "J'ai été obligé à terminer ce travail par mon chef." is grammatically correct it sounds very unnatural. No one would say that in real speech. Sounds as if something was wrong in the structure.
John a obligé Jack à lui donner son sac
=> Jack a été obligé par John de lui donner son sac
How come we'd say "de" here and not "à" like in the previous example?
Well... to be fair I don't know why, maybe there's no reliable rule, just real-world usage, but I wouldn't say "à" for sure.
You'd better stick with "John a obligé Jack à lui donner son sac"
(counterpart: Jack a été obligé de donner son sac)
The reason is essentially to do with usage patterns and analogy.
Once upon a time, "obliger à/de" behaved much more like "continuer à/de"-- i.e. there was essentially not real meaning distinction between the two. Littré, for example (a major descriptive dictionary of the mid 1800s and often cited in this kind of comparison) notes:
"Des grammairiens ont voulu distinguer entre obliger à et obliger de suivis d'un infinitif. L'usage n'établit aucune distinction : obliger de faire ou obliger à faire ; l'oreille seule en décide."
Now, one of the factors in "l'oreille seule en décide", is, for example, that writers would avoid using "à" after a verb form ending in -a, including many passé simples. So it would once have been normal to write:
Jean m'obligea de lui donner...
to avoid putting two "a" sounds together (cf. obligea à).
Nowadays, with the passé simple pretty much fallen out of natural usage, a major usage pattern with obliger de in an active form has disappeared, and usage is falling towards using à with active tenses and de with passives, influenced surely by usage with other adjectives such as content/heureux/triste de... etc.
The case that's still a bit in limbo is where you have a passive accompanied by an agent (i.e. the "doer of the action" is mentioned in a phrase par ...), as in my example, where there's a conflict between the adjective + de pattern, and the usage of obliger à when obliger is definitely a conjugated verb (since putting in the agent par ... makes it strongly sound like a "true" passive-- i.e. a conjugated verb, not a "simple adjective"). But it's interesting to note that the use of à sounds unnatural to you, and surely many other speakers will also get the same judgement. (Of course, a confusing factor here is simply that the passive per se isn't always very natural in French-- it can be difficult to judge which of two unnatural alternatives is the more unnatural...)